AM7911 AMD | Alldatasheet
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WORLD-CHIP® FSK Modem Devices DISTINCTIVE CHARACTERISTICS ___ Common Capabilities ® Complete FSK Modem in 28-pin package | Commercial, industrial and Extended "= 300-bps full-dupiex operation temperature range ™ No external filterin; red ™ 1200-bps half-duplex operation 'g requ ® Alldigital signal processing, digital filtering, @ = 1200-bps full-duplex on four-wire and My Dik onversion chin 9 = Compatible with Bell 103/113/108, Bell 202, ™ Includes essential RS-232/CCITT V.24 CCHT V.21, and v.23 handshake signals on-chip ™ avaliable In CDIP, PDIP, and PLCC packages ™ Autoanswer capability Unique Device Capabilities Am7910 Am7911 ® Dial-up network response times | Fast response time for leased-line networks ™ Bell 202 with 5-bps back channel Bell 202 with 5-bps or 150-bps back channel ™ v.23 with up to 75-bps back channel ™ _V.23 with up to 150-bps back channel “BLOCK DIAGRAM capt cape FD ica Reco RC <7 no Demodulator pnaiog a aACACAu) had Eee D cj = | BTD An RIS — BATS iS yet = Bers FESET XTALVCLKXTALZ ec VBB_AGNO DGND 09829¢-001 WORLD-CHIP is a registered trademark of Advanced Micro Devices, Inc. Publication ® 04262 Rev. D Amendment 0 Issue Date: June 1989 ,
Advanced Micro Devices offers a family of high- ‘on-chip features include: analog-to-digital and digital- performance FSK modem chips that may be easily inte- to-analog converters, internal crystal oscillator, and the grated in system designs to interface terminals and essential RS-232/CCITT V.24 terminal contro! signals workstations to the Telephone Network. The product with TTL levels. A DAA (Data Access Arrangement) or family consists of: acoustic coupler must be supplied externally to provide * _am7910 FSK Modem the Phone Line Interface.
4 The FSK modem chips all have the same basic structure
“Am7911 FSK Modem as shown in the simplified block diagram. The Am7910 ~Am79101 Autodial FSK Modem and the Am7911 differ mainly in timing parameters with the Am7911 being tailored for better performance in Am7910 and Am7911 leased-line, multidrop applications. The Am7911 also AMD currently offers three single-chip modems in the includes an extended set of modem selection modes. Frequency Shift Keying (FSK) series including the . Am7910, the Am7911 and the Am79101. This family of The Am79101 is described in a separate data sheet modems includes most of the building blocks required (order no, 09833). for a complete communication system. Some of the
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Full-Duplex oo. 0... cece cece eee eee cree tenet eaeeeeeeneeeenaereneces 16 Hall-Duplex 20... cece ccee cece cece eeeee eee eeeteteeneeesaereneess 16 FUI-DUplex oo... cece ccc eee ee eee eee ee eet eteteteeeeteeeenne 19 Halt-Duplex oo... 20 ee ceeee cere cece eee ee eet neeee eee eneeeeee cence e 19 Timing Parameters... 2.20000 eee eee ee cee e eee teen eee e ee teeeeee ee cee BF LOOPHACK 22.2... eee cece eee e eee een eee ete e eee ee cers ect ce recess BF Am7910/11 3 :
a ge & ea B aEskege Poi fi fifi fit RING] 1° 28 |] BTD 4 3 2 1 2 27 26 vec] 2 27) BCD rcL]5 251 | oo RESET| RD Ue 26 capt [_] 6 24] xTaLveuk ves] 4 257) 0D CAP2 ‘Al rcC] 5 24 [2 xTALCLK C7 za[ | xTal2 caPi(] 6 23 [7] xTAL2 teL_] 8 22{_] DGND cap2[] 7 22 [_] DGND acnp [_] 9 21 |] Mca tc 8 21 [ymca AGNDE] 9 20) mcs to[_] 10 20 | _] mcs ToL 10 19 [7] Mc2 BATS} 11 19 |] mc2 BRTS( 11 18 [ct 213 «14 «15 ~16 =17_~18 RISC 12 17 wco CTOorcoy trol oo a ex os 13 16[otr Es B 26E€8 8 BOTS 14 15 [7] BRD Note: Pin 1 is marked for orientation. 09560-98 Ee
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a
ORDERING INFORMATION
AMD standard products are available in several packages and operating ranges. The ordering number (Valid Combination) is formed by a combination of: a. Device Number b. Speed Option (if applicable) ©. Package Type d. Temperature Range ~ ©. Optional Processing AM7910/11 D c B LL ©. OPTIONAL PROCESSING Blank = Standard Processing B = Bum-in d. TEMPERATURE RANGE C= Commercial (0°C to +70°C) | = Industrial (40°C to +85°C) E = Extended (-55°C to +125°C) . PACKAGE TYPE P = 28-Pin Plastic DIP (PD 028) D= 28-Pin Ceramic DIP (CD 028) J = 28-Pin PLCC (PL 028) b. SPEED OPTION Not Applicable a. DEVICE NUMBER/DESCRIPTION ~ Am7910/11 WORLD-CHIP FSK Modem AM7910 PC, JC, DC, AM7911 DCB, DI, DIB, DE, DEB 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 combinations, and to obtain additional data on AMD's standard military grade products. a Am7910/11 5
All digital inputs and outputs are TTL-compatible unless otherwise noted. Setup Controls AGND that it belongs to the back channel. Since the modem Analog signal ground pin (for TRANSMITTED contains single transmitter, RTS andBRTS should not CARRIER and RECEIVED CARRIER). be asserted simultaneously. BRTS is meaningful only — when a 202 or V.23 mode is selected by MCO-MC4. In BCD all other modes, it is ignored. Back Carrler Detect For the V.23 modes and the 202 150-bps (or 75-bps) This line is equivalent to CD for the main channel, _ back channel mode, the frequency appearing at the TC except it belongs to the back channel. BCD is meaning- (Transmitted Carrier) output pin is determined by a Mark ful only when a 202 or V.23 mode is selected by MCO— or Space at the BTD input. MC4. For the V.23 back channel mode or the 202 BAR arti For the 202 5-bps back channel mode, a frequency of aes aaa High. No energy (0.0 volts) appears at TC whenBRTS is Sufficiars level at the FIG (Recalved Gamer input High. BTD should be fixed High for 202 back channel For the 202 5-bps back channel mode, BCD turnsonin —_ transmission. BATS then is equivalent to the transmit- response to a 387 Hz tone of sufficient level atthe RC _ted data. BATS is the Secondary Request-to-Send for input. In this case BCD is equivalent to the secondary 202 S/T modems, or the Supervisory Transmitted Data received line signal detector for 202 S/T modems, or for 202 C/D modems. supervisory received data for 202 C/D modems. D —— BT Bets Back Transmitted Data Back Clear to Send This line is equivalent to TD forthe main channel, except This line is equivalent to BCTS for the main channel, it belongs to the back channel. BTD is meaningful only except it belongs to the back channel. BCTS is mean- when a 202 or V.23 mode is selected by MCO-MC4. For ingful only when a V.23 mode or 202 150-bps (or 202 5-bps back channel transmission of on/off keying, 75-bps) back channel mode is selected by MCO-MC4. BTD should be fixed at a High level. This signal is not used in the 202 5-bps back channel mode. CAPs, CAP2 Connection points of external capacitor/resistor BRD required for proper operation of the on-chip analog-to- Back Recelved Data digital converter. Recommended values are: This line is equivalent to RD for the main channel, C = 2000 pF #10%, except that it applies only to the back channel. BRD is R = 910 ohms #10%. meaningful only for the V.23 or the 202 back channel _ modes. Under the following conditions this output is CD clamped High: Carrier Detect © V.21/103 modes A Low on this output indicates that a valid carrier signal . is present at the receiver and has been present for at = BCD High least a time (tepoy). A High on this output signifies that no = DTR High valid carrier is being received and has notbeen received for a time (tcoorr)- CD looks for energy in the receive ™ BATS Low and ATS High in V.23 or 202 150-bps bandwidth. CD is Low when the receive signal is above a threshold limit (Veoo,) and High when the level of the modes only : i received signal is belOW Veooer- © During autoanswer sequence. =< @ in crs BRTS Clear to Send Back Request to Send This output goes Low at the end of a delay (trcox) initi- Since the 1200-bps modem configurations (Bell 202 ated when RTS goes Low. Actual dala to be transmitted and CCITT V.23) permit only half-duplex operation over should not be presented to the TD (Transmit Data) input two-wire lines, alow baud rate back channel is provided _until a Lowisindicated onthe CTS output. This gives the for simultaneous transmission in the reverse direction. receiving modem (on the other end of the phone line) BRTS is equivalent to RTS for the main channel, except enough time to recognize a valid carrier signal before
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data is transmitted. Normally the user should force the configuration (transmit over one channel and receive on TD input High whenever CTS is High so a Mark willbe another). See the System Configuration section for sent during the (tacox) time. CTS goes High attheendof —_—_ details. a delay initiated when RTS goes High (trorr)- CTS will ag never be Low when DTA is High. ived Carrier DGND This input is the analog signal received from the phone Digital signal ground pin. line. The modem extracts the information contained in — this modulated carrier and converts it into a serial data _ OTR stream for presentation at the RECEIVED DATA (BACK Data Terminal Ready RECEIVED DATA) output. ALow level on this input indicates the data terminalis RD ready to send and/or receive data via the modem. This (Recelved Data) Sn ate a these aipals ae welras the Data bits demodulated from the RC (Received Cartier) i T logic. A High di I TTL VO pit input are available serially at this output; High (Mark) in- intemal control logic. A High disables al Pins dicates logical 1 and Low (Space) indicates logical 0 and the internal logic. a pace) es : DTA is Hi Under the following conditions, this output is forced to When D is High, the modem handshake state Paige machine is reset to initial conditions. This is the only way _‘'09ical 1, because the data may be invalid: toresetthe state machine and must be done after power —When Cb is High up. The state machine does not automatically power up to aknown state. IfDTR is permanently enabled (Low), —During the internal squelch delay at half-duplex line the state machine will simply run from wherever it pow- tumaround (202 and V.23 modes only) ers up. This can result in abnormal behavior such as an . . . unusually short RTS-CTS delay due to lack of DTR —During soft carrier turnoff at half-duplex line turn- initialization. around (202 and V.23 soft turn-off modes only) Inorderto change the modem mode while the modem is —When DTR is High ered up, use the following sequence: Powered, na sea —When RTS is Low and BATS is High in 202 and V.23 — 1, Take DTR High modes only 2. Change mode inputs to desired configuration 3. Wait at least 100 ns —During the autoanswer sequence 4. Take DTR Low RESET The mode inputs perform some hardware functions. and This input signal is for a reset circuit which operates in they are also sampled periodically by the state machine. either of two modes. Referto Figure 15 and Figure 16 for lithe mode inputs are changed without the re-initializa- —_ these two modes. The Am7910/11 shouldbe reset upon tion using DTA, the state machine will not completely —_jnitial application of power. change to the new mode. MCO-MC Th i t signal permits autoa bility by jis input signal permits autoanswer capability by Mode Controls ; responding to a ringing signal from a Data Access The FSK modem famiy has matiple bull mone Arrangement. If a ringing signal is detected (Ring = Low) nodes sele le user through a set of le DTA is Le i Control Pins, Table 1 ists the modem modes, mode- SCaeructan Se Ie aire te owe control pin states, and the product containing a particu- lar mode. RTS The loopback modes set the receiver channel signal © Request to Send processing band to that of the transmit channel. No Low on this input instructs the modem to enter the _~ _ internal connection is made. The user must connectthe transmit mode. This input must remain Low for the dura- TC pinto the RC pin if analog loopback is required (see —_tion of data transmission. This signal has no effect it Figure 1). DTR is set High (disabled). A High level on this input For digital loopback, external connection of the RD and _‘tw"ns off the transmitter. TD pins is required. Te With the Am7910/11, loopback modes canalsobeused Transmitted Carrier to achieve full-duplex, 1200-bps communication. In _This analog output is the modulated carrier to be condi- CCITT V.23 or Bell 202 loopback modes, the modem —_ tioned ine est ee phone line. can transmit and receive at 1200 bps using a four-wire Am7910/11 7 .
Transmitted Data +5-volt power supply (+5%). is | clock frequency must be 2.4576 MHz +.01%. Table 1. Am7910/11 Mode Control Lines
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Figure 1. Analog Loopback
the block diagram—Transmitter, Receiver, and Inter- encodes one bit per baud. A logical 1 applied to the TD. Frequency Shift Keying (FSK) modulation. This analog Synthesized sine functions. Figure 2. Transmitter Block Diagram. than the two used in the modulation. Allthe transmitted __°Y @ Simple on-chip analog low-pass fier.
- The phone companies have specifications on the _ecover the binary data to appear at the RD pin. ACD
bands on the line. carrier to indicate valid data.
- If two independent information channels are The short control signal delays on the Am7911 make it
nents may fall in the frequency band of the local re- line utilization when polling. ponents are attenuated by digital bandpass filters.
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Figure 3. Receiver Block Diagram modem andthe localterminal. Itconsists primarilyofde- Proceed as depicted in the flowcharts. ling transmission and reception, and mode-contro-de- sed inthese flowcharts are depicted in Figures 4 and. levels under certain conditions (for example, initial con- and CCITT V.23.
Table 3. Frequency Parameters
- (RTS Low) and (BTD High) : 387 Hz at TC.
- GATS High) or (BTD Low) : 0 Volts at TC.
Note: Full-duplex applies to all 103/113 and V.21 modes. Figure 4. Full-Duplex Channel Assignments
300 T 4501300 | 2100 390 1 450 1300 T4700
Note: Half-duplex applies to 202 and V.23 modes, both main and back channels. Figure 5. Half-Duplex Channel Assignments
Before two modems can exchange data, an electrical —_ upper right-hand portion of Figure 6. Assume that DTR connection through the phone system must be estab- has recently been asserted to cause exit from the initial lished. Although it may assist in call establishment, a conditions. Note that it DTR remains OFF, Ring is modem typically does not play a major role. Acall may —_ ignored. Assume also that RTS andBATS are OFF and be originated manually or automatically and it may be that the mode control lines (MCO-MC2) select a normal answered manually or automatically. modem configuration, not a loopback mode. Automatic Manual Calling—Manual calling is performed by a per- answering is initiated by receipt of a Low level at the son who dials the number, wais for an wer then Fing input, causing entrance 10 the autoanswer places the calling modem into data transmission mode. sequence depicted in Figure 8. Automatic Calling—Automatic calling is typically per- The modem outputs silence (0.0 volts) at its Transmitted formed by an automatic calling unit (ACU) which gener- Carrier (TC) output for a time, tax for the V.21 and V.23 ates the appropriate dialing pulse or dual-tone modes. TheCD pinis clamped OFF and the RD signal is sequence required to call the remote (called) modem. therefore clamped to a Mark (High) during the The ACU also has the ability to detect an answer tone autoanswer sequence. Upon completion of the answer fromthe called modem and place the callingmodeminto tone, CD is released. If the mode lines (MCO-MC4) data transmission mode. select a 202 or V.23 mode, the transmit filters are set to an the forward channel and the receive fitters are set to the Manual Answering—Manual answering is performed back channel during the autoanswer sequence. by a person who hears the phone ring, lifts the receiver, causes the called modem to send an answer tone to the Atthe end of the autoanswer sequence, aretum is made calling modem, and places the called modem into data to point A in the loop at the upper right-hand portion of transmission mode. Figure 6. Note that since the answer flag has been set, the autoanswer sequence cannot be entered again Automatic Answering—Automatic answering is per- _uniess DTA is first turned OFF, then ON. At this point the formed by a called modem with a data access arrange- phone line connection has been established and data ment (DAA). The DAA detects a ringing signal, takes the fransmission or reception may begin. Phone circuit off-hook (corresponding to lifting the receiver) and instructs the called modem to commence The Ring input may be activated from a conditioned the autoanswer sequence. Next the called modem DAA Ring indicator output for automatic answering or it sends out silence on the line, followed by an answer may be activated by a switch for manual answering. tone. When this tone is detected by the calling modem, Tying Ring High will disable the autoanswer function of the connection is considered to have been established. the modem. The modem provides assistance for automatic answer- ing through the Ring signal as follows. Observe the
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[no] Gite tte oe Li, GRE!
Full-Duplex the TC output which follows the Mark/Space applied to Following call establishment, full-duplex data transmis- TD. RTStuming ON initiates a delay, tacon, al the end of sion can be started by either the called or calling Which the CTS output goes Low. When CTS goes Low, modem. In other words, if the connection has been _—_-ata may be transmitted through input TD. Data trans- established andthe modemis looping through point Ain __- mission continues until RTSis turned OFF. At this time Figure 6, it no longer matters which is the called and Several events are initiated. First a delay (tacor) is initi- which is the calling modem. Data transmission is initi- ated al the end of which CTS turns OFF. The TD inputis ated by asserting RTS. At this time the TD input willbe ignored as soon as RTS goes OFF. If a 202 mode or released and a modulated carrier can appear at the TC _V..23 soft turn-off mode is selected, a soft turn-off tone output. Following a delay, lacon, CTS will turn ON. Atthis appears at the TC output for a time (Lero) followed by si- time, data may be transmitted through the TD input. Itis lence (0.0 volts). For both 202 and V.23 modes a a common protocol for the user to always present a Squelch period, te, is initiated when RTS goes OFF. Mark at the TD input before RTSis asserted andduring During this period the CD output is clamped OFF, forc- the treo, delay. ing the RD output to a Mark condition. The squelch . . a period begins as soon as RTS goes OFF and thus over- Data transmission continues until RTS is tumed OFF. Japs both trcorr ANd testo. At the end of the squelch period, Following a short delay, treorr, CTS tums OFF. As soon _the state machine retums to the idle loop at point A in as RTS goes OFF, the TD input is ignored and the TC _Figure 6. output is set to 0.0 volts (silence). After CTS turns OFF, the state machine returns to point A in Figure 6. The reasons for squelch and soft-turnoff are as follows: Soft Turn-Off—When RTS is turned OFF at the endot a Half-Duplex message, transients occur which may cause spurious When ahalt-duplex mode is selected (202 or V.23),data_ _SPace Signalsto be received at aremote modem. During transmission can be either on the main channel at Soft tum-off the modem transmits a soft carrier fre- 1200/600 baud or on the back channel at 5/75/150 quency for a period (tero) after RTS is turned OFF. This baud. in normal half-duplex operation a single modem is results in a steady Mark on the RD line of the remote either transmitting on the main and receiving on the modem. back channel! or vice versa. In the modems, control of the transmitter and receiver fters to the proper channel ili local receiver must be turned OFF after ' nar ee, is OFF, until the start of carrier detect, so that line is performed by RTS. When RTSis asserted, the trans- transients are not demodulated. The process of dis- miter filters and synthesizer are set to transmit on the abling the receiver after RTS i tumes OFF is called main channel; the receiver filters are set ta receive on thing 's 's cal the back channel. Therefore, whenever ATS is on, SWe!Ching BRTS should not be asserted since the transmitter can- not be used forthe back channel. WhenRTSis OFF and Back Channel a half-duplex mode is selected, the transmitter filters This transmission sequence, shown in Figure 7, is and synthesizer are set to the backchannel; the receiver entered if a 202 or V.23 mode is selected. RTS is OFF, filters are set to the main channel. RTS andBRTS are aNd BRTS is asserted. The BCD output is forced OFF asserted simultaneously, RTS will take precedence. andthe BRD output is clamped to a Mark. The BTD input However, if BRTS is asserted before RTS and the back _—is released and a carrier appears at the TC output which channel data transmission sequence has been entered ‘follows the Mark/Space applied to BTD. Turing on (Figure 7), RTS will be ignored until BATS is turned BATS initiates a delay (lecaox) at the end of which the OFF. BRTS output goes Low. When BRTS goes Low data ; may be transmitted through input BTD. Data transmis- The state machine sequences for main and back chan- sign continues until BATS is turned OFF. The input BTD. nel transmission differ slightly and are depicted in is immediately ignored and the TC output is silenced Figures 6-9. Assume the state machine is idling through __/S ‘Nmediataly ignofed and the TC output is sie point A in Figure 6. {setto 0.0 volts). Following a short delay (lercorr) the out- Put BCTS goes OFF. The signals BCD and BRD are re- Main Channel ny and the state machine retums to idle at point A of This transmission sequence is entered if a 202 or V.23 , mode is selected and ATS is asserted. Since the _'" 202 5-bps back channel mode, BTD should be tied receiver is now forced to the back channel, the RD sig- High. ThenBRTS controls the ON/OFF keying modula- nal is clamped to a Mark, and the CD signal is clamped _tion. When BRTS is Low, 387 Hz appears at the TC OFF. The TD input is released and a carrier appears at output; when BRTS is High, 0 volts appears at TC.
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Figure 7. Transmit Back Channel State Diagram
Figure 8. Autoanswer State Diagram
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a DATA RECEPTION Data reception is controlled by state machine 2 and RTS controls whether the main channel is transmitting depicted in Figure 9. At power on the machine enters or receiving. The back channel can do only the opposite initial conditions and remains there until DTR is fromthe main. If RTSis OFF, thenCD may be activated asserted. It then loops until eitherCD or BCD occurs. and the data reception sequence is identicat to that dis- cussed above for full-duplex reception. As long as RTS Full-Duplex remains OFF, BCD will neverbe activated. If RTSis ON, In full-duplex data reception, CD may appear at any thenGD wil revere activated Instead the receiver wil ____ time after the phone connection has been established. for a valid carrier in ick channel frequency Reception is Independent of transmission. When the aNd. valid carer exists for at least atime (tow) the receiver detects a valid carrier for al least a time (lex) Ulput BCD is tued ON, the BRD output is released the output CD is turned ON, the RD output is released, and valid data can be obtained at BRD. Data is received and valid data can be obtained at RO. Data is received _ Until the receiver detects loss of back channel fecelved tntthe receiver detects loss of cari foratleast atime _SiaMal for at least a time (lcor). At this time the BCD (teoon). At this time the CD output is tumed OFF and RD _oUtPut is tuned OFF. Data output, BRD. is clampedto a is clamped to a Mark. The state machine returns tothe Markit a V.23 mode or 202 150-bps back channel mode idle loop at point E. is selected. For 202 5-bps back channel mode, BCD represents the received data. The BRD output canbe ig- Half-Duplex noted. The state machine returns to the idle loop at As discussed in the data transmission section above, point E. when a half-duplex mode has been selected the signal a Am7910/11 19 .
Figure 9. Receiver Main/Back Channel State Diagram
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Table 4. Am7910 Timing Parameters Note: @- @ eter to designations on timing diagrams in Figures 10,11, 12, and 13.
Table 5. Am7911 Timing Parameters
- Soft turn-off tone is generated only for selected V.23 modes.
Note: @- @ reter to designations on timing diagrams in Figures 10,11, 12, and 13.
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a LOOPBACK CLOCK GENERATION Eleven modes exist to allow both analog and digital Master timing of the modem is provided by either a crys- loopback for each modem specification met by the tal connected to the XTAL: and XTAL2 pins or an exter- Am7911 (ten modes for the Am7910). When a loopback nal clock applied to XTAL:. mode is selected, the signal processing (filters, etc.) for both the transmitter and receiver is set to process the Crystal same channel or frequency band. This allows the ana- . . log output (TC) and the analog input (RC) to be con- When acrystal is used it should be connected as shown nected for local analog loopback. Alternatively the digi- in Figure 14. The crystal should be a parallel resonance __ tal data signals (TD and RD or BTD and BRD) can be _‘YPe, and its value must be 2.4576 MHz +:.01% Alist of connected externally, allowing a remote modem to test "Stal suppliers is shown below. the local modem with its digital data signals looped back. External Clock When a loopback mode is selected, the state machine This clock signal could be derived from one of several sequences are altered slightly. First, autoanswer is dis- __°rYStal-driven baud rate generators. It should be con- abled, Second, if a half-duplex loopback mode is nected to XTAL: and XTAL2 must be left floating. The selected (202 or V.23), the local SOIBED isnot forced timing parameters required ofthis clock are shown in OFF when RTS/BATS is asserted. Figure 15 and the values are listed in Table 6. The 202 and V.23 main loopback modes allow use in a Crystal Information (f = 2.4576 MHz) four-wire configuration at 1200 bps. eT orvmo—9—' Manufacturer PIN ci c2 Four-Wire, Full-Duplex M-Tron MP-2 10 pF 20 pF The modem can be configured to work full-duplex over Monitor Products © MM-33 10 pF 20 pF four-wires by selecting one of the loopback modes. The. <<< loopback modes allow independent operation of the Note: Rise time of Vcc must be greater than 5 ms to ensure transmitter and the receiver within the modem. proper crystal oscillator start-up. The 202 and V.23 main loopback modes allow full-du- plex communication of up to 1200 bps over four-wires. a a | | | | XTAL: CLOCK, XTAL,"* OL 2.4576 MHz “6 XTAL; NG. XTAL; ~ | ! | | * Capacitor values vary with different crystal manufacturers. ** The input impedance of this pin appears as 5 to 10 pF to ground in parallel _ with at least 1 Megohm. Figure 14, Clock Generation a Am7910/11 27 ,
Figure 15. External Clock Table 6. Clock Parameters automatically whenever Vcc is applied. Vcc rise time Figure 18. clock period. cally close to the pins as possible. be High for at least 1 1s, as shown in Figure 17. Figure 16. Automatic Reset
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Figure 17. Reset Timing Diagrams Figure 18. Mode Setup
5 Vde 09833A-31
Figure 19. Power-Supply Connections
ABSOLUTE MAXIMUM RATINGS OPERATING RANGES All Signal Voltages with Respect ou ° Stresses above those listed under ABSOLUTE MAXI- MUM RATINGS may cause permanent device failure. Functionality at or above these limits is not implied. Exposure to absolute maximum ratings for extended periods may affect device reliability. SS
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a DC CHARACTERISTICS (over operating ranges unless otherwise specified) Digital inputs: MC0-MC4, DTA, BRTS, TD, BTD, RTS,RING Digital Outputs: GTS, BCTS, CD, BCD, RD, BRD a Parameter Parameter Symbol Descriptions Test Conditions: Min. Typ. Max. Unit a Vow Output High Voltage lon = 400 mA. Cio = 50 pF 24 Vv a Vou Output Low Voltage lu =2mA Cp = 50 pF C,I Devices 04 v E Devices 06 v ee Vw Input High Voltage 20 Vee v a Va Input Low Voltage 05 08 v a Vie External Clock Input High (XTAL:) 38 Veo Vv linn lA Vac External Clock Input Low (XTAL:) 05 08 v a Vow External Reset Input High (Reset) 38 Veo v a Var External Reset Input Low (Reset) 05 08 v we Ls Digital Input Leakage Current 0.0 < Va< Voc -10 10 pA a han Resot Input 0.0 < Vw < Voc Leakage Current C,l Devices 0.75 0.75 pA E Devices -1.0 1.0 pA a kee Voc Supply Current C Devices 140 mA {Devices 160 mA E Devices 170 mA eT las. Ves Supply Current C Devices 15 mA | Devices 20 mA E Devices 25 mA a Cour Output Capacitance 1= 1.0 MHz 15 pF a Cu Input Capacitance {= 1.0 MHz 15 pF an Vee Positive Supply Voltage ATS 5.25 v le Vee Negative Supply Voltage 4.75 5.25 Vv ee ~~ AGND, Ground Offset 50 50 mv DGND a Am7910/11 31 .
‘Standard Load Circult Test Point Voc From ba) Pe Output Output 19502 1% Test D2 Cy R Dg al 48 Ki1% D4 09833A-24 Notes: 1. C1 = 50 pF including stray and wiring capacitance 2. Alldiodes are 1N3064 or equivalent 3. All resistors are 1/8 watt 4. Voc = 5 Volts + 5%
32 Am7910/11
SWITCHING CHARACTERISTICS over operating ranges Parameter Parameter ‘Symbot Descriptions Min, Typicat Max. Unit Part ee Transmitter Vre TC Output 0.548 Vs Voltage -3.0 dBm oe — Vroce TC DC Offset 100 100 mV PaO Toe. Delay trom TD to TC Change 83 Bs ee face Frequency Accuracy (Except 202) 04 04 Hz eee thee Frequency Accuracy 202 Mark 1.0 1.0 Hz A Recelver Vee RC Input Voltage 16 1.6 v ae Rw Input Resistance 50 Kohms ee Vecos Allowed DC Input Offset -30 +30 mV tne frou Frequency Deviation Tolerance 16 16 Hz —_—— ees Veoon Carrier Detect on Level 40.5" 68m 7910 ~ ~42.0° dBm 7911 Veoore Carrier Detect off Level 450° dBm 7910 75 48m 7911 Vos Carrier Detect Hysteresis 45° 8 7910 55° 6B 7911 Note: All TC levels are measured using a 600 ohm load. All dBm measurements are referenced to 600 ohm. * nominal spread = +1 dB Out-of-Band energy: See Figure 16 ee Performance Figure 20 shows a graph of nominal bit error rates forthe various modem types. A flat line condition, back-to-back wire connection, is used to allow easy correlation by users. oe Am7910/11 33
10 N :
Figure 20. Am7910/11 Nominal Bit Error Rate
34 Am7910/11
FREQUENCY (kHz) aza4 160 A | 0 Ci gO | oe A _ oes A | oe | eo 2 a | 35 a Pa «| eeprom IL WT TT Ths ihe Ove Lael Ras ote _ peeps Cir eg | UU PT Ti Pri PT iT 0.01 0.1 02 1.0 10.0 100 Figure 21. Out-of-Band Transmitter Energy
APPLICATIONS
The Am7910 and Am7911 allow designs for many FSK System Configurations —~ applications. The AMD Modem Technical Manual goes Since the Am7910 and Am7911 are multi-mode into details on many different applications with specific modems, one basic modem design can be used to meet examples. The Modem Technical Manual also gives both North American and International market require adgitional information on the hybrid (Figure 19) andline ments, Under the control of a microcontroller such as interface design (Figure 20) (Order No. 09560C). the Am8031/51, the modems canbe easily reconfigured from one mode to another with no hardware changes. Stand-Alone Modem Both modems are autoanswer, but to implement A stand-alone modem can be configured using the autodial an external DTMF generator is required. A ‘Am7910/11 RS-232/V.24 line drivers and receiver, a _Sister chip, the Am79101 includes full autodial support phone line interface (DAA or acoustic coupler), anda _—with integral OTMF generation, Call Progress Tone two-to-four wire hybrid. A modem suitable for connec- Detection, and Answer Tone Detection. The four- to tion to a serial computer port is shown in Figure 17. tWo- wire hybrid function is also on-chip. Since the Am7910/11 interfaces only to TTL-level de- in contrast to the standard two-wire dial-up or switched vices, RS-232/V.24 line drivers and receivers are re- network, most dedicated networks use four-wire leased auired for connection to devices accepting standard —_jines. The Am7910 and Am7911 can be easily config- -232/V.24 voltage levels. ured for four-wire full-duplex operation at 1200 bps. The Automatic answering of the telephone can be assisted Am7911 is the recommended modem for this applica- by the Am7910/11 in this arrangement. Once the DAA _tiondue tothe short RTS/CTS delay timing which allows has been placed in the off-hook state by the user'sinter-__ ™ultidrop operation on four-wires. Figure 18 shows an face, the DAAwillassert RING onthe Am7910/11. This example of the Am7910/7911 under the control of an — answertone conforms tothe Bell and CCITT V.25 stan. AMB051; the modem is placed in analog loopback to dards on duration, frequency, and amplitude. Tying allow 1200 bps full-duplex operation. The line interface RING High on the Am7910/11 disables the generation typically comprises two line isolation transformers of the answer tone. with a simple line impedance matching network and appropriate protective diodes. a Am7910/11 35
1 ALB FESET r,
P— Me, Veo -5V “Value as recommended by crystal manufacturer. e Mey peno| to ground (C = 0.33pF, R= 100kQ).
2 Neo V ALB = Analog Loopback Local Copy
Figure 22. Stand-Alone 7910/11 Application
36 Am7910/11
6000 XTAL1 — XTAL2
600.0 MGi +——J P14 Porto
Figure 23. 1200 bps Four-Wire Full-Duplex Circult Figure 24. Four-to-Two Wire Active Hybrid Circuit
1 Hook
Figure 25. Am 7910/11 Phone Line Circuit
38 Am7910/11 :
PHYSICAL DIMENSIONS PD 028 1.440 [a i480 - $30 1) 580 Ir ai “a 110 005
085 MIN
$80 015 620 060 140 | or 225 { is 008 —- 015
125 O14
-160 023 068428 a cD 028 1.435 — 1.490 098 MAX 605 TIE
050 SC 005
$90 01S 615, a 060 008 160 | O12 220 t x .150 4 } MIN : i olla 015 L700 _ yj
022 MAX
a Am7910/11 39 ,
PHYSICAL DIMENSIONS (continued) PL 028 042 —— 020 048 050 MIN REF jr 025 942 045 056 ooomehrhm A | q a) H 0 .300 REF 485, q 0 290 495 — 026 3 q HW — cose 4.013 | 430 480] 0 021 456 : q 0 Dooooo 008, 450 015 090 ASE 120 485 165. 495 180 sree ‘Ravanced Were Devices reserves the rightto make changes in ila product witout notte in order io improve design or performance characteristics, The perfomance ‘characteristics listed in this document are guaranteed by speciic tests, guard banding, design and other practices common to the industy. For specific testing details, Contact your local AMD sales representative. The company assumes no responsibly for he use ol any Grcults described herein Advanced Micro Devices, Inc. 90' Thompson Place, P.O. Box 3453, Sunnyvale, CA 94088, USA ‘© 1989 Advanced Micro Devices, inc. Pa | ‘Tek: (408) 732-2400 - TWX: 910-339-9280 + TELEX: 34-6306 + TOLL FREE: (800) 538-8450 .. See APPLICATIONS HOTLINE TOLL FREE: (800) 222-9323 + (408) 749-5703 ' wy ore72s Ye -