AM79101 AMD | Alldatasheet
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Am79101 PRELIMINARY DATA SHEET Am79101 FSK AUTODIAL MODEM PRELIMINARY DATA SHEET
PRELIMINARY AM79101 DATA SHEET PRODUCT SPECIFICATION: THE Am79101 FSK AUTODIAL MODEM PRELIMINARY DATA SHEET DECEMBER 1987
CONTENTS
DISTINCTIVE CHARACTERISTICS -.-..+eeeee-seeeeeeeeeerseees 5 GENERAL DESCRIPTION ...-erersveescsccererssseecaccsscanes 6 ORDERING INFORMATION ...-eeeeecer cere ecererccrseeeeresere 8 PIN DESCRIPTION ....seeeseesccersceneeeeesececseeaeeerees 9 Setup Controls Transmitter I/0 Receiver I/O Miscellaneous FUNCTIONAL DESCRIPTION ..ceeseccccesceseessrsreweerercnre 18 Transmitter Receiver Interface Control CALL ESTABLISHMENT «2... seeeeececsccssecerececrcseessesere 23 Call Progress Tone Detection (CPTD) Dual-Tone Multi-Frequency (DTMF) Tone Generation Answer Tone Detection Answer Tone Generation DATA TRANSMISSION ..-ee-cesceeesereccrcrcrrrercrsseresens 30 Full-Duplex Half-Duplex Main Channel Soft Turn-off Squelch Back Channel DATA RECEPTION ..---esccsccscsccccescsereessecnsasesasens 32 Full-Duplex Half-Duplex Sele) :) \\o) Ge ee eee ee 32 CLOCK GENERATION ...ceeecenccacceereesseneneerearereesees 43 RESET MODES 2. ee eeeccsecercc ret erscressceacnersssenseeeee 44 POWER SUPPLY -.-seeececcecrerceeesaceesresreceranessaseee 45
PRELIMINARY AM79101 DATA SHEET ABSOLUTE MAXIMUM RATINGS ..cceccsceecerererccsssensssenas 46 DC CHARACTERISTICS .eeeeeeecscesscsceccesctsccccesssccees 47 SWITCHING CHARACTERISTICS ....eeseeesescsseeeeeecessaeeee 49 PERFORMANCE cece ccccscscescececcceccerersnenaeeaseaneeee 50 APPLICATIONS 6. cece csssc rs ce ccs cecneeecnseeeeereneeereee 52 PHYSICAL DIMENSIONS Stee eae c ee eeeeereeererereacaraccceee 55
PRELIMINARY AM79101 DATA SHEET Am79101 FSK AUTODIAL MODEM WORLD-CHIPTM DISTINCTIVE CHARACTERISTICS ° Bell 103, 113, 108 and CCITT V.21 compatible at 300 bps full-duplex ° Bell 202 and CCITT v.23 compatible at 1200 bps half-duplex with up to 150 bps back channel (CCITT V.23 modes with optional soft carrier turn-off feature) ° Single-chip digital signal processor ° Autodial support -Dual Tone Multi-Frequency (DTMF) Tone Generation ~Call Progress Tone Detection -Answer Tone Detection ° Integral 4-to-2 wire hybrid ° Public Switched Telephone Network (PSTN) response times ° Serial RS-232C/CCITT V.24-type handshake interface and protocol
PRELIMINARY AM79101 DATA SHEET GENERAL DESCRIPTION The Am79101 World-Chip is a single-chip asynchronous Frequency Shift Keying (FSK) modem that is compatible with the applicable Bell and CCITT-recommended standards for 103/113/108, 202, V.21 and V.23-type modems. All modulation, demodulation, filtering, analog-to-digital and digital-to-analog functions are provided on-chip. Using the features described here, an intelligent Autodial, Autoanswer FSK modem may be implemented with only an Am79101 single-chip under the control of a host microprocessor and a Data Access Arrangement (DAA) circuit. The modem operates in a serial asynchronous mode; the serial interface supports the RS-232C/CCITT V.24-type handshake signals at TTL levels. The modem analog interface provides an internal hybrid for the 4-to-2 wire conversion. Auxiliary functions performed within the Am79101 include: - Autodial support with DTMF generation and Call Progress Tone Detection. - Answer Tone Detection (Bell and CCITT). - Autoanswer support. - Analog loopback support. The Am79101 is housed in a 28-pin plastic leaded chip carrier as well as 28-pin plastic and ceramic dual-in-line packages. Connection to the telephone network may be via a DAA or an acoustic coupler. All digital I/O signals are TTL-compatible (except the external clock and RESET signals) and the circuit operates from +5 Volts. = we = avavave a ee [Le | = [| Hi 2 = i a. =i [core] pl mcs we |Am79101 Block Diagram ~—:
PRELIMINARY AM79101 DATA SHEET CONNECTION DIAGRAMS Top View DIP PLOG DACA (1% 287] sto § & " bal SH SSE Be col y2 27E) B05 Hono RESET (9 28[7] no fs 3 2 1 7 ew | Yee C4 Fo) mao) rel] 5 ° 25] re (]s 24 [7] TAL 0K OM] 6 2417} XTAL (CLK cay 6 23[7] xan CAPA] 7 23[-) XTALg om 7 22/7] Dano tel] s 22) Deno tee aah cd. ny wey AGND [_] 9 2) Mi To C}10 19 [7 we, ro 0 aps BATS C}11 18 [7] Mc, Bars] 11 te 10f) MS AIS Chiz 177] Mey ee
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PRELIMINARY AM79101 DATA SHEET
ORDERING INFORMATION
AMD products are available in several packages and operating ranges. The order number (valid combination) is formed by a combination of the following: a. Device number b. Speed option (if applicable) c. Package type a. ‘Temperature range e. Optional processing Am79101 D ¢ B L e. Optional Processing Blank = Standard processing B= Burn-in d. Temperature Range c = Commercial (0°c to +709C) I = Industrial (-40°C to +85°C) E = Extended (-55°c to +125°C) c. Package Type D = 28-Pin Ceramic DIP (CD 028) P = 28-Pin Plastic DIP (PD 028) J = 28-Pin PLCC (PL 028) a. AMD Device Type b. Speed option FSK Modem Not Applicable Valid Combinations Am79101 ] DC, DCB, Di, DIB, PC, DE, DEB, Jc Valid Combinations Valid Combinations list configurations planned to be supported in volume for this device. Consult the local AMD sales office to confirm availability of specific valid combinations, to check on newly released valid combinations, and to obtain additional data on AMD's standard military grade products.
PRELIMINARY AM79101 DATA SHEET PIN DESCRIPTION All digital inputs and outputs are TTL-compatible unless other- wise noted. SETUP CONTROLS DA/CA Data/Call (Input) This input_selects the Data Mode (DA/CA=HIGH ) or the Call Mode (DA/CA=LOW). In the Data Mode, the Am79101 operates as a modem, using other setup and handshake inputs. Data Mode is the initial condition by default. To enter the Call Mode, DA/CA is brought to a LOW while DIR is HIGH and Mc pins are set to a valid mode (i.e., not reserved mode). Once in the Call Mode, DTR is set Low. MC inputs and RTS will determine tha generation of either DIMF or answer tones, and the detection of call progress tones or answer tones. To re-enter the Data Mode, DA/CA is returned to a HIGH during a valid modem mode. DIR Data Terminal Ready (Input) A LoW level on this input indicates the data terminal is ready to send and/or receive data via the modem. This signal is gated with all other TTL inputs and outputs so that a LOW level enables these signals as well as the internal control logic. A HIGH disables all TTL 1/0 pins and the internal logic. When DIR is HIGH, the modem handshake state machine is reset to initial conditions. This is the only way to reset the state machine, and must be done after power-up. The state machine does not automatically power up to a known state. If DTR is permanently enabled (LOW), the state machine will simply run from wherever it powers-up. This can result in abnormal behavior such as an unusually short RTS-CTS delay due to lack of DTR initialization.
PRELIMINARY AM79101 DATA SHEET To change the modem mode when powered-up, use the following sequence: (See Figure 16) 1. Set DIR HIGH 2. Change McC inputs to desired configuration 3. Wait at least 100 microseconds 4. Set DIR Low The MC inputs perform some hardware functions and are also sampled periodically by the state machine. If the MC inputs are changed without re-initialization using DTR, the state machine will not_completely change to the new mode. In the Call Mode, DTR does not have to be changed when going from one DIMF digit to another. MCo-MCg Mode Controls (Inputs) In the Data Mode, the MC inputs specify one of the 25 available modem configurations as listed in Table la. Included are Bell 103/202, CCITT V.21/V.23 with various options like equalizer, 150 bps back channel, soft turn- off and loopback. The loopback modes set the signal processing frequency band of the receiver to that of the transmitter. The user must connect TC to RC for analog loopback, and RD to TD for digital loopback as shown in Figure 1, In the Call Mode, the MC inputs select generation of DIMF or answer tones, or detection of call progress tones or answer tones, as listed in Table lb. None of the reserved modes should be used. TRANSMITTER 1/0 BCTS Back Clear To Send (output) This line is equivalent to CTS for the main channel except that it applies only to the back channel. BCTS is meaningful only when a V.23 mode or 202 150bps (or 75bps) back channel mode is selected by MCo-MC,. This signal is not used in the 202 5bps back channel mode.
PRELIMINARY AM79101 DATA SHEET BRITS Back Request To Send (Input) Since the 1200bps modem configurations, Bell 202 and CCITT v.23, permit only half-duplex operation over 2-wire lines, a low baud rate back channel is provided_for simultaneous transmission in the reverse_direction. BRTS is directly equivalent to main channel RTS, except that it applies only to the back channel. Note that since the modem contains a single transmitter, RTS and BRTS should not be asserted simultaneously. BRITS is meaningful only when a 202 or V.23 mode is selected by MCo-MCq. In all other modes, it is ignored. For the V.23 modes and the 202 150bps (or 75bps) back channel mode, the frequency appearing at TC is determined by a Mark or Space at BTD. For the 202 5bps back channel mode, a frequency of 387 Hz appears at TC when BRTS is LOW and BTD is HIGH. No energy (0.0 Volts) appears at TC when BRTS is HIGH. BTD should be held HIGH in this_mode. BRTS then, 1s equivalent to the transmitted data. BRTS is the Secondary Request-to-Send for 202 S/T modems, or the Supervisory Transmitted Data for 202 C/D modems. BID Back Transmitted Data (Input) This line is equivalent to TD for the main channel, except that it applies only to the back channel. BTID is meaningful only when a 202 or V.23 mode is selected by MCo-MCq. For 202 Sbps back channel transmission of on/off keying, BTD should be set HIGH. CTs Clear To Send (Output) This output goes LOW at the end of a delay (trcon) initiated when RTS goes LOW. Actual data to be transmitted should not be presented to TD until a Low is indicated on CTS. This gives the receiving modem (on the other end of the phone line) enough time to recognize a valid carrier signal before data is transmitted. Normally the user should force TD HIGH whenver CTS is HIGH so a Mark will be sent during the tpcon_time. CTS goes HIGH at the end of a delay initiated when RTS goes HIGH (trcoFF)- CTS will never be LOW when DTR is HIGH. RTS Request To Send (Input) A LOW on this input instructs the modem to enter transmit mode. This input must remain LOW for the duration of data transmission. This signal has no effect if DIR is HIGH (digabled). A HIGH level on this input turns off the transmitter.
PRELIMINARY AM79101 DATA SHEET In the Call Mode, RTS also controls the transmitter. When RTS is LOW, the tone specified by the MC pins will be transmitted. A HIGH level will turn off the tone. During Answer Tone Detection and Call Progress Tone Detection, RTS should be HIGH. Tc Transmitted Carrier (Output, Non-TTL-Compatible) This analog output is the modulated carrier to be sent over the phone line. Its frequency changes according to the data at TD or BTD. TD Transmitted Data (Input) Data bits to be transmitted are presented to this input serially; HIGH (Mark) corresponds to logic 1 and LOW (Space) corresponds to logic 0. This input determines which frequency to appear at any instant at TC (See Table 3). No signal appears at TC unless DIR is Low and RTS is LOW. RECEIVER I/O BCD Back Carrier Detect (output) This line is equivalent to CD for the main channel, except that it applies only to the back channel. BCD is meaningful only when a 202 or V.23 mode is selected by MCo-MCg._ For the V.23 or 202 150bps (or 75bps) back channel modes, BCD changes to Low when either the Mark or Space frequency appears with sufficient level at Rc. For the 202 5bps back channel mode, BCD changes to LoW in response to a 387 Hz tone of sufficient level at RC. In this case BCD is equivalent to the signal, Secondary Received Line Signal Detector, for 202 S/T modems, or Supervisory Received Data for 202 C/D modems. BRD Back Received Data (Output) This line is equivalent to RD for the main channel, except that it applies only to the back channel. BRD is meaningful only for the V.23 or the 202 back channel modes. Under the following conditions this output is clamped HIGH: 1. V.21/103 modes 2. BCD HIGH 3. DIR HIGH 4. BRTS LOW and RTS HIGH in V.23 or 202 150 bps modes only 5. During Autoanswer sequence.
PRELIMINARY AM79101 DATA SHEET @® Carrier Detect (output) A LOW on this output indicates that a valid carrier signal is present at the receiver and has been present for at least the time topoy- A HIGH on this output signifies that no valid cagrier is being received and has not been received for at least the time SEDOEF: In the Data Mode, Carrier Detect looks for energy in the receive bandwidth. A carrier is considered valid when the signal level at RC is above a threshold limit Vcpon, and absent when the level is below VcpoFF: In the Call Mode, a CD LOW output indicates a valid answer tone or call progress tone has been detected above the limit Vepcon- A CD HIGH output indicates there is no energy above the Vcpcorr- RC Received Carrier (Input, Non-TTL-Compatible) This input is the analog signal received from the phone line. The modem extracts the information contained in this modulated carrier and converts it into a serial data stream at RD or BRD. RD Received Data (Output) Data bits demodulated from RC are available serially at this output; HIGH (Mark) indicates logic 1 and LOW (Space) indicates logic 0. Under the following conditions, this output is clamped HIGH because the data may be invalid: 1. When CD is HIGH 2. During the internal squelch delay at haif-duplex line turn-around (202 and V.23 modes only) 3. During soft carrier turn-off at half-duplex line turn- around_(202 and V.23 soft turn-off modes only) 4. When DTR is HIGH 5. When RTS is LOW and BRTS is HIGH in 202 and V.23 modes only 6. During Autoanswer sequence. MISCELLANEOUS AGND Analog Ground
PRELIMINARY AM79101 DATA SHEET CAP1, CAP2 (Non-TTL-Compatible) These two pins are connection points for the external series capacitor-resistor required for proper operation of the on-chip analog-to-digital converter. Recommended values are: C = 2000 pF +10% R = 910 ohm +10% DGND Digital Ground RESET (Non-TTL-Compatible) This input signal is for a reset circuit which operates in either of two modes (refer to Figures 15a and 15b). The Am79101 should be reset upon initial application of power. VBB -5 Volt Power supply vcc +5 Volt Power Supply XTAL], XTAL2 (Non-TTL-Compatible) Master timing of the modem is provided by either a crystal connected to these two pins or an external clock inserted into XTAL]. The value of the crystal or the external clock frequency must be 2.4576 MHz +.01%.
PRELIMINARY AM79101 DATA SHEET Table la. Mode Controls in the Data Mode (DA/CA=HIGH) ° ° [) ° [) Bell 103 originate 300 bps full-duplex ° ° ° 0 1- |Bell 103 Answer 300 bps full-duplex ° ° ° 1 © |Bell 202 1200 bps half-duplex with 5 bps back channel tC) ° ° 1 1 |Bel1 202 1200 bps with amplitude equalizer and 5 bps back channel ° ) 1 ° 0 |ccrTT v.21 originate 300 bps full- duplex ° 0 1 ° 1 |¢CITT v.21 Answer 300 bps full-duplex () ° 1 a © |ccITT v.23 Mode 2 1200 bps half-duplex* ° +) 1 1 1 |ccrrr v.23 Mode 2 with amplitude equalizer 1200 bps half-duplex* ° 1 ° ° 0 |cCCITT v.23 Mode 1 600 bps half-duplex* C) 1 ° ° 1 |Reserved ° 1 ° 1 0 |Bell 202 1200 bps with 150 bps back channel C) 1 ° 1 1 |Bell 202 1200 bps with amplitude equalizer and 150 bps back channel ° 1 1 ° 0 |ccITT v.23 Mode 1 600 bps with soft turn-off* 0 2 1 ° 1 |Reserved 0 1 1 1 0 |cCITT v.23 Mode 2 1200 bps with soft turn-off* ° 1 1 1 1 |ccrrr v.23 Mode 2 1200 bps with amplitude equalizer and soft turn-off* #Up to 150 bps back channel is available. Note: Reserved modes should not be entered.
PRELIMINARY AM79101 DATA SHEET Table la. Mode Controle in the Data Mode (DA/CA = HIGH) (Continued) = a T 0 0 0 0 [Bell 103 originate loopback 1 ° ° ° 1 |Bell 103 Answer loopback 1 oO ° 1 0 Bell 202 main loopback 1 ° 0 z 1 | Bell 202 with amplitude equalizer loopback 1 ° 1 ° 0 CCITT V.21 originate loopback 1 0 1 0) 1 CCITT V.21 Answer loopback 1 ° 1 1 ° CCITT V.23 Mode 2 main loopback 1 ° 1 1 1 CCITT V.23 Mode 2 with amplitude equalizer loopback 1 1 ) [) 0 CCITT V.23 Mode 1 main loopback 2 1 ° ° 1 CCITT V.23 back loopback* 1 1 o 1 ° Bell 202 150 bps back loopback 1 2 ° 1 1 1 1 1 ° ° 2 1 1 tC) 1 |_|Reserved 1 1 1 1 ° 1 1 1 1 1 * Up to 150 bps back channel is available. Note: Reserved modes should not be entered.
PRELIMINARY AM79101 DATA SHEET Table lb. Mode Controls in the Call Mode (DA/CA=LOW) Fe A [SIN NEST eS O ° C) ° C) DIMF 0 or Answer Tone Detection [) ° ° o 1 DIMF 1 ° 0 ° 1 ° DIMF 2
0 C) Oo 1 1 DIMF 3
te) 0 1 0 0 DIMF 4 9 ° 1 ° 1 DIMF 5 0 9 1 1 0 DIMF 6 °o oO 1 1 1 DIMF 7 ° 1 ° [) ° DIMF 8 0 1 9 °o 1 DIMF 9 o 1 0 1 ° DIMF * 0 1 ° 1 1 DIMF # ° 1 1 0 0 Bell 103 Answer Tone °o 1 1 ° 1 Bell 202 Answer Tone O 1 1 1 o V.21 or V.23 Answer Tone ° 1 1 1 1 Call Progress Tone Detection 1 x x x x Reserved Note: Reserved modes should not be entered.
Figure 1. Loopback Configurations Am79101 are listed in Table 3.
PRELIMINARY AM79101 DATA SHEET In addition to this primary information band, there are side bands containing redundant information. It is desirable to attenuate these bands for two reasons: 1. The phone companies have specifications on the amount of energy allowed in certain frequency bands on the line. 2. If two independent information channels are present simultaneously on the line (e.g., 300 bps full-duplex or 1200 bps half-duplex with back channel), the redundant transmitter components may fall in the frequency band of the local receiver channel and interfere with detection. In the Am79101 these redundant and undesirable components are attenuated by digital bandpass filters. Following the digital bandpass filters, the filtered FSK signal is converted to an analog signal by an on-chip Digital-to- Analog Converter (DAC) operating at a high sampling rate. This analog FSK signal is made smooth by a simple on-chip analog low-pass filter. In the Call Mode, the sine synthesizer generates the DTMF or answer tones as specified by the MC inputs. These tones are then processed like the FSK signal and eventually appear at TC. Table 4 shows the DIMF tone combinations. Receiver (Demodulator) A simplified block diagram of the Am79101 FSK receiver is shown in Figure 3. Data transmitted from a remote-site modem over the phone line is a FSK-modulated analog carrier. This carrier is applied to the RECEIVED CARRIER (RC) pin via a DAA or an acoustic coupler. The first stage of the demodulator is a simple on-chip analog low-pass anti-alias filter. The output of this is converted into digital form and filtered by digital bandpass filters to improve the signal-to-noise ratio and reject other independent channel frequencies associated with the phone line in the case of full-duplex configuration. In the Data Mode, the bandpass-filtered output is digitally demodulated to recover the binary data to appear at the RECEIVED DATA (RD) pin. A Carrier Detect signal (CD) is also digitally extracted from the received line carrier to indicate valid data. In the Call Mode, the MC inputs select the proper digital bandpass filters to detect answer tones or call progress tones at RC. Presence of a valid tone will be indicated by CD. The on-chip hybrid provides the analog interface which communicates TC and RC directly over two wires to and from the telephone line via a DAA.
under certain conditions (e.g., initial conditions). the back channel signals are non-functional. state machines proceed as depicted in the flowcharts. applies to 202 and V.23, both main and back channels. CCITT V.21 can be operated full-duplex. transmit at 1200/600 bps and receive at 5/75/150 bps. 1200/600 bps. Examples are Bell 202 and CCITT V.23. Table 2. Initial Conditions
Table 3. Frequency Parameters
- (BRTS LOW) and (BTD HIGH): 387 Hz at TC.
- (BRTS HIGH) or_(BTD LOW): 0 Volts at TC.
** No 387 Hz at RC: BCD HIGH.
PRELIMINARY AM79101 DATA SHEET First, the Mode Control (MCo-MC4) pins are used to set up the modem’ mode. Next, the Call Mode is entered by setting DA/CA=LOW (see pin description). DTR is then set LOW once at the beginning of the Autodial or Autoanswer sequence. RTS remains HIGH except when tones are required to be transmitted. Now the MC pins can be used to select the above Autodial/Autoanswer features, as defined in Table lb. Autodial begins by using the CPTD function to detect the proper dial tone from the central office. The DIMF digit to be dialed is then input to the Mc pins and the transmitter generates the corresponding DIMF tones at the TC pin. After the last digit is sent, CPTD is used again to detect the ringback signal. Following the detection of ringback, the ATD feature can be used to detect the answer tone from the called modem. Following detection of the correct answer tone, data transfer can now begin. Figures 6a and 6b show the Autodial flowchart and timings. As a called modem, the Am79101 will be placed in the Call Mode by the external microprocessor which receives a ring indication signal from the DAA. Autoanswer begins by using ATG. Figures Ja and 7b show the Autoanswer flowchart and timings. Gall Progress Tone Detection (CPTD) The CPTD filter passes call progress tones from all the major Post Telephone and Telegraphs (PTTs). The cadences (temporal patterns) of CD will identify the following signals: Primary Dial Tone Secondary Dial Tone Ringback Signal Network Busy Signal Busy Signal Each country's PTT may have different requirements for the cadences of these call progress tones. Dual Tone Multi-Frequency (DTMF) Tone Generation The Am79101 transmitter can generate the basic 3 x 4 matrix, as shown in Table 4. According to the Bell specifications, the minimum duration for the DIMF digit is 50 ms. The minimum interdigit interval (silence) is 45 ms. The minimum time from the beginning of one DIMF digit to the next is 100 ms. It is common practice to extend the DIMF digit duration to insure detection by the central office. Once in the Call Mode, RTS controls the duration of the DIMF tone, With DIR=LOW and the desired digit applied to the MC pins, setting RTS=LOW will generate the DIMF tone at Tc until
PRELIMINARY AM79101 DATA SHEET RTS is set HIGH. The user has complete control of the DTMF tone duration and the interdigit interval. Inputs to the MC pins should be changed while RTS is HIGH and DTR is Low. Answer Tone Detection (ATD) The Am79101 receiver can detect answer tones for the Bell 103, 202, and CCITT V.21/V.23 modes. CD=LOW indicates the presence of a valid answer tone. RD distinguishes between the three answer tones as shown below. This feature allows mode matching with the remote modem. In the CCITT V.21/V.23 modes, X at RD indicates toggling between HIGH and LOW. Modem Mode Answer Tone Frequency (Hz) CD RD Bell 103 2225 Low HIGH Bell 202 2025 Low Low CCITT V.21/V.23 2100 Low x The Carrier Detect Call thresholds (Vepcon, Vepcorr) for valid answer tone detection are internally set to be higher than those in the Data Mode. This eliminates the need for an external attenuator in the Call Mode to prevent noise from being decoded as an answer tone. Answer Tone Generation (ATG) Answer tones are generated according to the modem mode selected, as listed in the ATD section. RTS=LOW controls the answer tone duration and RTS=HIGH controls the silence intervals. Silence interval before the answer tone is required by various governmental agencies for billing delay purposes.
PRELIMINARY AM79101 DATA SHEET MODE ROPER (ame | <>o om “TONE om —2<GE> Ces ENTER PROPER TMF DIGIT ON MODEM MODE MC PINS ENTER DATA MODE RTS Low FOR DTA DURATION TS HIGH. (STOP TONE) Last Mc PINS, TRANSFER ATS REMAINS HIGH FOR SILENCE DUR. To Fig. 88.09 LUNE BUSY, CD FOR START. Yes Figure 6a. Autodial Flowchart
PRELIMINARY AM79101 DATA SHEET Fr . fe] : FE — ai, 5 a @ 2 ia e | ; es | G 2 [as] [| H § E € & @ 8 g j
PRELIMINARY AM79101 DATA SHEET To Fig. 8a0r8 Figure 7a. Autoanswer Flowchart
Table 4. DIMF Tone Combinations
PRELIMINARY AM79101 DATA SHEET DATA TRANSMISSION* Full-Duplex Following call establishment, full-duplex data transmission can be started by either the called or calling modem. If the connection has been established and the modem is looping through point A in Figure 8a, it no longer matters which is the called and which is the calling modem. Data transmission is initiated by setting REQUEST TO SEND (RTS) LOW. At this time the TRANSMITTED DATA (TD) input will be released and a modulated carrier can appear at the TRANSMITTED CARRIER _ (TC) output. Following a delay, tpcon, CLEAR TO SEND (CTS) changes to LOW. At this time, data may be transmitted through TD. It is common protocol for the user to always present a Mark at TD before RTS is asserted and during the trcon delay. Data transmission continues until RTS is set HIGH. Following a short delay, trpcorr, CTS changes to HIGH. As soon as RTS goes HIGH, TD is ignored and Tc is set to 0.0 Volts (silence). After CTS changes to HIGH, the state machine returns to point A in Figure 8a. Half-Duplex When a half-duplex mode is selected (202 or V.23), data transmission can be either on the main channel at 1200/600 bps or on the back channel at 5/75/150 bps. In normal half-duplex operation a single modem is either transmitting on the main and receiving on the back channel or vice-versa. In the Am79101, control of the transmitter and receiver filters to the proper channel is performed by RTS. When RTS is asserted, the transmitter filters and synthesizer are set to transmit on the main channel; the receiver filters are set to receive on the back channel, Therefore, whenever RTS is LOW, BRTS should not be asserted since the transmitter cannot be used for the back channel. When RTS is HIGH and a half-duplex mode is selected, the transmitter filters and synthesizer are set to the back ghannel;_the receiver filters are set to the main channel. If RTS and BRTS are asserted_simultaneously, RTS will take precedence. However, if BRTS is asserted before RTS and the the back channel data transmission sequence has been entered (Figure 8b), RTS will be ignored until BRTS is set HIGH. The state machine sequences for main and back channel transmission differ slightly and are depicted in Figures 8a and 8b. Assume the state machine is idling through point A in Figure 8a. * All timing delays are listed in Table 5.
PRELIMINARY AM79101 DATA SHEET Main Channel This transmission sequence is entered if a 202 or V.23 mode is selected and RTS is asserted. Since the receiver is now forced to the back channel the RECEIVED _DATA (RD) signal is clamped to a Mark, and the CARRIER DETECT (CD) signal is clamped HIGH. The TRANSMITTED DATA (TD) input is released and a carrier appears at the TRANSMITTED CARRIER (TC) output which follows the Mark/Space applied to TD. RTS going LOW initiates a delay, trcon, at the_end of which the CLEAR TO SEND (CTS) output goes LOW. When CTS goes LOW, data may be transmitted through TD. Data transmission continues until RTS is set HIGH. At this time several events are initiated. First a delay, trcorr, is initiated at the end of which CTS goes HIGH. TD is ignored as soon as RTS goes HIGH. If a 202 mode or V.23 soft turn-off mode is selected, a soft turn-off tone appears at TC for a time, tgro, followed by silence (0.0 Volts). For both_202 and v.23 modes, a squelch period, tgg, is initiated when RTS goes HIGH. During this period the CD output is clamped HIGH, forcing the RD output to a Mark condition. The squelch period begins as soon as RTS goes HIGH and thus overlaps both trcorr and tgpo. At the end of the squelch period, the state machine returns to the idle loop at point A in Figure 8a. The reasons for squelch and soft turn-off are as follows: Soft turn-off: When RTS goes HIGH at the end of a message, transients occur which may cause spurious Space signals to be received at the remote modem. During soft turn-off the modem transmits a soft carrier frequency for a period, ts7o, after RTS goes HIGH. This results in a steady Mark on the RECEIVED DATA (RD) line of the remote modem. Squelch: The local receiver must be turned off after RTS is HIGH, until the start of carrier detect, so that line transients are not demodulated. The process of disabling the receiver after RTS goes HIGH is called squelching. Back Channel This transmission sequence, shown in Figure 8b, _is_entered if a 202 or V.23 mode is selected, RTS is HIGH, and BRTS is asserted. The BACK CARRIER DETECT (BCD) output is forced HIGH and the BACK RECEIVED DATA (BRD) output is clamped to a Mark. The BACK TRANSMITTED DATA (BTD) input is released and a carrier appears at the TC_output which follows the Mark/Space applied to BTID, Setting BRTS LOW initiates a delay, tprcon, at the end of which the BACK CLEAR TO SEND (BCTS) output goes LOW. When BCTS goes LOW data may be transmitted through BTD. Data transmission continues until BRTS is set HIGH. BTD is immediately ignored and Tc is silenced (set to 0.0 Volts). Following a short delay, tprcorr, BCTS goes HIGH. The signals BCD and BRD are released and the state machine returns to idle at point A of Figure 8a. In 202 5 bps back channel mode, BTD
when BRTS is HIGH, 0.0 Volts appear at TC. Figure 9. At power-on, the machine enters initial conditions teporr: At this time CD goes HIGH and RD is clamped to a Mark. The state machine returns to the idle loop at point E. identical to that discussed above for full-duplex reception. Mark if v.23 mode or 202 150 bps back channel mode is selected.
- All timing delays are listed in Table 5.
PRELIMINARY AN79101 DATA SHEET the same channel or frequency band. This allows the analog output, TC, and the analog input, RC, to be connected externally for local analog loopback. Alternately the digital data signals, TD and RD or BID and BRD, can be connected externally, allowing a remote modem to test the local modem with its digital data signals looped back. When a loopback mode is selected, the state machine sequences are altered slightly. If a half-duplex loopback mode is selected (202 or V.23), the local CD/BCD is not forced HIGH when RTS/BRTS is asserted.
PRELIMINARY AM79101 DATA SHEET LO [=r | a ae ws e = [oom] ES be co) Figure 8a. Transmit Main Channel state Dingran
PRELIMINARY AM79101 DATA SHEET <=> Ken) Sy) Figure 8b. Transmit Back Channel State Diagram
Figure 9. Receiver Main/Back Channel State Diagram
Table 5. Timing Parameters
Table 5. Timing Parameters (Continued)
59 Receiver
- For V.23 Soft Turn-off modes only.
Figure 10. Bell 202 Handshake Timing
- tp is an external delay provided by the user; tp > 0.
Figure 11. CCITT V.23 Handshake Timing **
- tp is an external delay provided by the user; tp > 5 ms.
™ ir a « [eo] a -— ere tl ee ee ey DS eee ee ES Lol [al la} Lol ey TA eo pe Randonee wiwingee 7 his’ eining aiegran ts not vo scale. See Tanie 8 tor”
Figure 13. Bell 103/V.21 Handshake Timing*
45 Vee
6 Vde
Figure 17. Power-Supply Connections ratings for extended periods may affect device reliability. functionality of the device is guaranteed.
PRELIMINARY AM79101 DATA SHEET DC CHARACTERISTICS (over operating ranges unless otherwise specified) Digital Inputs: DA/CA, MCg-MCy, DTR, RTS, BRTS, TD, BTD, RESET Digital outputs: CTS, BCTS, CD, BCD, RD, BRD Para— Tes’ meters) Description Conditions Min Units Vou | Output HIGH Tou = -400 uA Voltage Crp = 50 pF v Vou | output Low Tou = 2 mA Voltage Crp = 50 pF ower TT ey rece eT Vin | input HIGH Voltage Vee | Vv Viz | Input Low Voltage v Vinc | External Clock Input HIGH (XTAL,) Veo | Vv Vine | External Clock Input Low (XTAL}) v Ving | External Reset Input HIGH (RESET) Veo | V Vir | External Reset Input_LOW (RESET) v Digital Input Leakage 0.0 < Vrn < Voc|-10 10 Current Titr | Reset Input 0.0 < Vin < Voc rf [| Leakage a a peer
PRELIMINARY AM79101 DATA SHEET DC CHARACTERISTICS (Continued) Para- Test meters| Description Conditions Min Units cfrent eid a current: ie si Current aie | E Pevises] | | Cour | output Capacitance f= 1.0 MHz 15 Cin | input Capacitance f= 1.0 Miz 15 Power Test Supply| Description Conditions Min |tTyp Units Veo Positive supply 4.75 Voltage VBB Negative Supply Voltage Ground Offset mV Standard Load Circuit PONT Yoo Notes: 1. C, = 50 pF including stray and wiring capacitance 2. All diodes are 1N3064 E oureat y toon or equivalent Dp 3. All resistors are TEST A > 1/8 watt J aKa 3 4. Veco = 5 Volts +5% Ly mst
PRELIMINARY AM79101 DATA SHEET SWITCHING CHARACTERISTICS DIMF and ATG Output Description Min | Typical Units Vir output Voltage 0.652 Vans LOW group “1.5 abn Output Voltage 0.820 Veus Var HIGH Group 0.5 apm Output Voltage 0.518 Vas Var Answer Tone -3.5 aBm Modulated Transmit Output Description Min | Typical Units Fe Output 0.516 Vas Vere Voltage “3.5 apm Tc De Vrcos Offset -100 mv Harmonics from VHARM Fundamental Delay from TD TpEL to TC Change Frequency face Accuracy (Except 202) Frequency facc Accuracy 1.0
202 Mark
Out-of-Band energy: See Figure 19
PRELIMINARY AM79101 DATA SHEET SWITCHING CHARACTERISTICS (Continued) Receiver Input Description Min | Typical Units RC Input Vre Voltage -1.6 1.6] Vv Input Resistance Frequency Deviation Tolerance 16 Vopon Carrier Detect On Level aBm Venorr Carrier Detect Off Level apm Vepcon Carrier Detect Call On Level 37 aBm VepcorF Carrier Detect Call Off Level “41 apn Vays Carrier Detect Hysteresis Note: All TC Levels are measured using a 1200 ohm Load. All dBm measurements are referenced to 600 ohm. PERFORMANCE Figure 18 shows a graph of nominal bit error rates for the various modem types. A flat line condition, back-to-back wire connection, is used to allow easy correlation by users.
4 PRELIMINARY AM79101 DATA SHEET
5S crsetPereeseceeeeuneberrreedbeererecsbesssessssesssecePereeresMesssseefeceeesssereeseeee de] ROCGIVE Level = -30dBm|. Figure 18. Am79101 Nominal Bit Error Rate
PRELIMINARY AM79101 DATA SHEET FREQUENCY (kHz) 3234 160 (Ty yt ty ty TT F ee ee pa ga oe ea ee pe a a 8 0 ee eat IN TTT 2s ; HN rte Hf o| — hatesonsindnameeetammeseu tL N HT col Bamarinemtegeeorwemnewcecmer TTT NT TT - LTT A TT a LT Tr A aL IT | Tit ft Ti T Tut 0.01 ot 02 10 10.0 700 Figure 19. Out-of-Band Transmitter Energy**
APPLICATIONS
An intelligent Autodial, Autoanswer FSK modem can be easily built with the Am79101. Figures 20 and 21 show implementations of full-duplex and half-duplex modes. For the full-duplex 103/V.21 modes, a single baud rate (300 bps) is used. With its on-chip UART, the single-chip microcontroller Am8051 provides a simple solution. The Am79101's RS-232C signals and setup controls are connected to the Am8051 as shown in Figure 20. MC4 conveniently controls the on-hook relay in the DAA circuit. MC4=0 activates off-hook and MC4=1 keeps on-hook during analog loopback for local testing. If DIMF dialing is not permitted on a particular telephone network, the relay contact can be rapidly made and broken for pulse dialing. Automatic answering of incoming calls is serviced like an interrupt routine by the Am8051. Upon ringing, the DAA interrupts the Am8051, which then places the relay off-hook and the Am79101 in the Call Mode to generate the answer tone. After the call is established or answered, the Am8051 has complete control to start data transfer.
directly into the DAA circuit, as shown in Figure 22. Figure 20. 300 bps Full-Duplex Modem
Figure 21. 1200 bps Half-Duplex Modem
6002 Y as
Figure 22. Data Access Arrangement
PRELIMINARY AM79101 DATA SHEET PD-028 ‘es als roves PL-028 Be 4 r= me Vics 828 am ad & Lf a =o fee MN. 188. es. —_| 180
ADVANCED MICRO DEVICES’ NORTH AMERICAN SALES OFFICES ALABAMA 0.000 cceeeccees (205) 882-9122 KANSAS... foe (819) 491-2115 ARIZONA 000 TILA (602) 242-4400 MARYLAND’ EINE (oi) 796-gato ‘CALIFORNIA, MASSACHUSETTS, IIUIIIND, (617) 273-9970 Suter Cty coccccscseseseses (219) 845-1524 MINNESOTA, EUININ EIS (612) 938-0001 N each (714) 752-6262 MISSOURI 000000000000 (314) 275-4415 San Diogo TI, (19) 560-7080 «NEW JERSEY IEEE. on) 298-0002 San Jose se ielec ieee secs sees (408) 249-7768 NEW YORK, Santa Clara 20000000000. {408) 727-3270 Liverpodl ose (315) 457-5400 ‘Woodland Hits | (818) 992-4155 Poughkeepsie DIENT, 114) 471-8180 CANADA, Ontario, Woodbury 0.00 1 (616) 364-8020 Kanata, ccssssseesssvesee (619) $92:9060 NORTH CAROLINA'S. 2000000000000 318) 847-8471 Willowdale 22000002 (410) 224-5193 OHIO nee TU (614) 891-6455, COLORADO. TUT. (Goa) 741-2900 ‘Columbus LINIIIITD (614) 891-6455 CONNECTICUT 22200000000 0a) 264-7800 Bayon on 1513) 439-0470 FLORIDA, ‘ORF DU UEEEEEAAS 245-0060 Clearwater... (813) 530-9971 PENNSYLVANIA, Melbourne... 2220000) Gos) 729-0496 Willow Grove: 20000000. (215) 657-3101 Orianda 202. {200} 258-0831 TEXAS, GEORGIA : 12 {aod} 449-7920 ‘Austin... cceeecetees sees (512) 946-7830 ALLINOIS, Dallas 20 [1 14) 934-9099 Chicago sesso . (312) 73-4a02 Houston 20000000000. 713) 785-9001 Kapenio -. 2 TIT (312) 505-9517 WASHINGTON |=: UII. (206) 485-3600 INDI TINII (17) 244-7207 WISCONSIN .0200000000.000. UIIIID (414) 792-0890 ADVANCED MICRO DEVICES’ INTERNATIONAL SALES OFFICES ‘Bruxelles voeeeeeees TEL fons 775 9 42 FAX 10.07.) 2-2-784-8014 FAX (02) 762 37 12 LATIN AMERICA, FRANCE, FAX (905) 485-9736 FAX 101! (1) 49-75-1013 NoRway, 1x 263282 HOVE cece ceeeeeeee TEL: (02) 537810 GERMANY, FAX 00000000, (02) 591959 FAX (05143) 55 53 Monchen . TEL (988) 41 14.0 FAX TL zest tg FAX... (088) 496490 TUX 001 AS85650 MMI RS Tux = 523883 FAX 21110711) 625187 FAX 010.0.2) (08) 733 22 85 mx 721882 Tx: fee ns HI6O2 HONG KONG, FAX 110") 952-123-4276 FAK 00121) 86-2-7122017 TLX |! “SOAZB0AMDAPHX UNITED KINGDOM, Famborough 2 TEL oo... (0252) 517431 ITALY, Milano cecceeeeees TEL cseess (02) 9390541 FAX 1102211 (0262) 521041 (02) 3593241 Tx ; 858051 TO 18286 FAX 10000007 (0925) 827693 JAPAN, TX ca 628524 FAX “T (03) 342-5196 FAK 202007 (04862) 22179 TUX... WadBAAMOTKOS Ta ‘859103 FAX 106-243-3253 NORTH AMERICAN REPRESENTATIVES CALIFORNIA MICHIGAN FING {Sem (408 988-2400 SAI MARKETING CORP <-+ 4818) 750-1922 DIST! (408) 498-6868 MISSOURI Gagan, Aberta NEBRASKA ITEL ELECTRONICS =» (403) 278-5833 LORENZ SALES ceseeeees (402) 475-4560 Kanata, Ontario NEW MEXICO Messeauge, Ontano NEW YORK Quebec OHIO VITEL ELECTRONICS (614) 636-5951 Columbus IDAHO DOLFUSS ROOT & CO... sss (614) 885-4864 ‘SAI MARKETING CORP 17) 253-1668 Stangsvile. LORENZ SALES «2... .cccsesesese (819) 977-4666 PENNSYLVANIA, LORENZ SALES (913) 384-6556 UTAH RE MARKETING. coeceeceseeseses (201) 595-0601 ‘Advanced Micro Devicas reserves the righ! to make changes in its product without notice in order to improve design or performance Characteristics. The performance characteristics listed in this document are guaranteed by specific tests, guard banding, design and cother practices common to the industry. For spectic testing details, contact your local AMD sales representative. The company assumes no responsibilty for the use of any circuits described herein. "ADVANCED MICRO DEVICES 901 Thompson Pi. PO. Box 2453, Sunnyvale, CA 94086, USA {© 1996 Advancod Micro Dewcee, nc TEL: (408) 702-2400 » TWX: 910-200-8280 @ TELEX: 54-6506 © TOLL FREE: (600) 538-8450 WCP-5M-2/88-0 APPLICATIONS HOTLINE TOLL FREE: (800) 222-9923