SAA5050

SAA5050 ETC

Document overview

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Technical content

| SAAS5O50 SERIES TELETEXT CHARACTER GENERATOR The SAA5050 series of MOS N-channel integrated circuits provides the video drive signals to the television receiver necessary to produce the teletext/viewdata display. The variants are described in the Quick Reference Data and full details of the characters sets are given in Figs. 11 to 18. QUICK REFERENCE DATA Supply voltage Vop nom. 5 Vv Supply current Ipp typ. 85 mA Operating ambient temperature range Tamb —20 to +70 °C Variant Character set + Variant Character set

5050 English 5054 Belgian

5051 German 5055 US ASCII

5052 Swedish 5056 Hebrew

5053 Italian 5057 Cyrillic

a v Vv © go Vss nc 3 18 1 iy 5 4 ao D20 CONVERSION 2 o30—% Hy e 7 INPUT 4 5 040 ROM GRAPHICS CHARACTE 0 CRS v70 O FI Ll 5 rae a | TIMING r | ° NS ho 285 Lose CONTROL 13 a, 16 CHARACTER yf © DEW TLC O DETECTION AND STORE FLASH COUNTER DISPLAY sow CONTROL cS] cote} — covour || ho 2 [7] muctiecexer PowER EMOTE 2 os avano as RESET rane | Yt 28| 27] 3] un} iz wozen OE PO BATR om GTR Fig.1 Block diagram PACKAGE OUTLINE 28-lead DIL; plastic (SOT—117) , July 1982 v Mullard

SAA5050 SERIES | | ground Veg [1 | U [28] DE display enable input superimpose 51. [2 | PO picture on input remote control data DATA [3 | [26] LOSE toad output shift register enable ot [4] [25] BLAN blanking output oz [5] j24] os [6 | [23] G } video outputs character data D4 B inputs SAASO50 os [8] [21] Y monochrome video output vs [9] {20} F1 1MHz input p7 [10] [19] TR6 6MHz input remote control data clock DLIM Vpp positive supply (+5V) general fine reset SUR [12 NC not connected data entry window DEW [13 [16] TLC transmitted large character character rounding select CRS [14] BCS big character select m8 1-1065/2/B Fig.2 Pinning diagram

DESCRIPTION

The SAASO50 is a 28 pin device which incorporates a fast access character generator ROM (4.3 k bits), the logic decoding for all the teletext control characters and decoding for some of the remote control functions. The circuit generates 96 alphanumeric and 64 graphic characters. In addition there are 32 control characters which determine the nature of the display. The SAA5050 is suitable for direct connection to the SAA5010, SAA5012, SAA5020 and SAA5040 Series integrated circuits. The basic input to the SAASO50 is the character data from the teletext page memory. This is a7 bit code. Each character code defines a dot matrix pattern. The character period is 1 ws and the character dot rate is 6 MHz. The timings are derived from the two external input clocks F 1 (1 MHz) and TRE (6 MHz) which are amplified and re-synchronised internally. Each character rectangle is 6 dots wide by 10 TV lines high. One dot space is left between adjacent characters, and there is one line space left between rows. Alphanumeric characters are generated on a 5 x 9 matrix, allowing space for descending characters. Each of the 64 graphic characters is decoded to form a 2 x 3 block arrangement which occupies the complete 6 x 10 dot matrix (Fig.9). Graphics characters may be either contiguous or separated (Fig.10). The alphanumeric characters are character rounded, i.e. a half dot is inserted before or after a whole dot in the presence of a diagonal in a character matrix. The character video output signals comprise a monochrome signal and RGB signals for a colour receiver. A blanking output signal is provided to blank out the television video signal under the control of the PO and DE inputs and the box control characters (see Table 3). The monochrome data signal can be used to inlay characters into the television video. The use of the 32 control characters provides information on the nature of the display, e.g. colour. These are also used to provide other facilities such as ‘concealed display’ and flashing words etc. The full character set is given in Table 1.

Teletext character generator circuit SAA5050 SERIES HANDLING Inputs and outputs are protected against electrostatic charge in normal handling. However, to be totally safe, it is desirable to take normal precautions appropriate to handling MOS devices (See ‘Handling MOS Devices’). RATINGS Limiting values in accordance with the Absolute Maximum System, (IEC134) min. typ. max. Voltages (with respect to pin 1) Supply voltage (pin 18) Vpp -0.3 - 75 Vv Input voltages (all inputs + input/output) vy —0.3 - 7.5 Vv Output voltage (pin 16) Voie ~0.3 _ 75 Vv {all other outputs ) Vo -0.3 - 14.0 Vv Temperature Storage temperature range Tstg —20 to +125 oc Operating ambient temperature range Tamb —20 to +70 °C CHARACTERISTICS min. typ. max. Supply voltage (pin 18) Vopb 45 - 5.5 Vv The following parameters apply at Tamp = 25 °C and Vpp = 5 V unless otherwise stated. Supply current Ibp - 85 160 mA Inputs Character data D1 to D7 (pins 4 to 10) Input voltage; HIGH VI 2.65 - Vpopb v Input voltage; LOW ViL 0 - 0.6 Vv Clock inputs F1 (pin 20) TR6 (pin 19) Input voltage; HIGH VIH 2.65 - Vpp Vv Input voltage; LOW Vit i‘) - O6 Vv Logic inputs DATA (pin 3) DEW (pin 13) LOSE (pin 26) DLIM (pin11) CRS (pin 14) PO (pin 27) GLR (pin 12) BCS (pin 15) DE (pin 28) Input voltage; HIGH ViH 2.0 - Vpp Vv Input voltage; LOW Vit i) - 41.8 Vv All inputs Input leakage current (Vj) = 5.5 V) lig _ - 10 pA Input capacitance Cc) - - 7 pF . July 1982 v Mullard

SAA5050 SERIES | | CHARACTERISTICS (continued) min. typ. max. Outputs Character video outputs + Blanking output (open drain) (note 3) B — (pin 22), G — (pin 23), R — (pin 24), Y — (pin 21), Blanking (pin 25) Output voltage; LOW (Ig, = 2 mA) VOL - - 0.5 Vv Output voltage; LOW (lo. = 4 mA) VoL - - 1.0 Vv Output voltage; LOW (Io, = 6 mA) VOL - - 2.0 Vv Output voltage; HIGH VOH Vpb - 13.2 Vv Output load capacitance CL - - 16 pF Output fall time \\ note 1 'f - - 30 ns Variation of fall time between any outputs J Ate i) - 20 ns TLC (pin 16) Output voltage; LOW (Iq, = 100 HA) VoL [) - 0.5 Vv Output voltage; HIGH (—IQH = 100 #A) VOH 2.4 - Vop Vv Output load capacitance CL - - 30 pF Output rise time | Measured between0.8V | tr - - 1.0 us Output fall time and 2.0 V levels lt - - 1.0 bs Input/output st (pin 2) (open drain) Input voltage; HIGH VIH 2.0 - 6.5 Vv Input voltage; LOW Mit 0 _ 08 Vv Input leakage current (Vj = 5.5 V) ir - - 10 BA Input capacitance Cy = = 7 pF Output voltage; LOW (Ig, = 0.4 mA) VoL 0 = 0.5 Vv Output voltage; LOW (Io, = 1.3 mA) VoL 0 - 1.0 Vv Output load capacitance CL - - 45 pF Output voltage; HIGH state (note 2) VOH — - 6.5 Vv duly 1982 | Mullard wi]

Teletext character generator circuit | SAA5050 SERIES Timing characteristics For typical display of 40 characters per line. Line rate = 64 us. Field rate = 20 ms. Character data timing (Fig.4) min. typ. max. TRE rising edge to F1 falling edge to 6 - 60 ons TR6 frequency ttre - 6 - MHz TR6 mark/space ratio 40:60 - 60:40 F1 frequency fr1 - 1 - MHz F1 mark/space ratio 40:60 - 60:40 Data set-up time icps 80 - - ons Data hold time tCDH 100 - = ns Delay time — character in/ | Graphics tcDG - 2.6 - BS character data at outputs Alphanumerics tepA - 2.767 _ us Display period timing (Fig.5) F1 falling edge to LOSE rising edge tLDH ie) - 250 ns F1 falling edge to LOSE falling edge tLDL 0 - 250 ns LOSE rising edge to ‘Display on’ tDON - 2.6 - ous LOSE falling edge to ‘Display off’ tDOFF - 2.6 - us ‘Display period’ top - 40 - BS Line rate timing (Fig.6) F1 rising edge to GLR falling edge tDGL () - 200 ns F1 rising edge to GLR rising edge tDGH 0 - 200 ns GLR LOW time tGLP - 1 - ous Line start* to GLR falling edge tGLR _ 5 - us Line start* to LOSE rising edge TLSL - 14.5 - LOSE falling edge to Line start* tLLs - 9.5 - us Line period tLNP - 64 - us LOSE HIGH time tLHP - 40 - us Remote data input timing (Fig.8) Assuming F1 period = 1 us and GLR period = 64 us DLIM clock HIGH time ICH 6.5 8 (note 4) HS DLIM clock LOW time ToL 3.5 8 60 us DATA to DLIM set-up time tps 0 14 — ons DLIM to DATA hold time tpH 8 14 — ps *Taken as falling edge of ‘line sync’ pulse. ve Mullard ] mys

SAASO050 SERIES | | Notes 1. Fall time, t¢ and A tg, are defined as shown and are measured using the circuit shown below: ty is measured between the 9 V and 1 V levels. A tg is the maximum time difference between outputs. | | tf at — —1.0V 08243 rr +12V Output pin gv clamp + 1SpF T max D8067b Vss Fig.3 2. Recommended pull-up resistor for SI is 18 kQ. 3. The R, G, B, Y and blanking outputs are protected against short circuit to supply rails. 4. There is no maximum DLIM cycle time, provided the DLIM duty cycle Is such that the tCL max requirement is not exceeded. SPECIAL FEATURES Flash oscillator The circuit generates a 0.75 Hz signal with a 3:1 ON/OFF ratio to provide the flashing character , facility. Power-on-reset When the supply voltage is switched on, the character generator will reset to tv, conceal, and not superimpose modes. mre \\ Mullard iv]

Teletext character generator circuit | SAA5050 SERIES Character rounding The character rounding function is different for the small and double height characters. In both cases the ROM is accessed twice during the character period of 1 us. The dot information of two rows is then compared to detect the presence of any diagonal in the character matrix and to determine the positioning of the character rounding half dots. For small characters rounding is always referenced in the same direction (i.e. row before in even fields and row after in odd fields as determined by the CRS signal). For double height characters rounding is always referenced alternately up and down changing every line using an internally generated signal. (The CRS signal is ‘0’ for the odd field and ‘1’ for the even field of an interlaced tv picture). Graphics decoder The 64 graphics characters are decoded directly from the character data inputs and they appear on a 2x 3 matrix. Figure 9 gives details of the graphics decoding. APPLICATION DATA The function is quoted against the corresponding pin numbers Pin No. 1. Vgs Ground - 0 Vv 2. $i Superimpose This is a dual purpose input/output pin. The output is an open drain transistor (capable of sinking current to Vgs), which is in the conducting state when superimpose mode is selected. This allows contrast reduction of the tv picture in superimpose mode if required. If the pin is held LOW, the internal ‘tv mode’ flip-flop is held in the ‘text’ state. This is for VDU applications when the remote control is not used. 3. DATA Remote control data This input accepts a 7-bit serial data stream from the remote control decoder. This data contains the teletext and viewdata remote control functions. The nominal data rate is 32 us/bit. The command codes used in the SAA5O50 are shown in Table 2. 45,6 D1 to D7 Character data 78,8, These inputs accept a 7-bit parallel data code from the Page memory. This data selects the 10 alphanumeric characters, the graphics characters and the control characters. The alphanumeric addresses are ROM column addresses, the graphics and control data are decoded internally. 11. DLIM This input receives a clock signal from the remote control decoder and this signal is used to clock remote control data into the SAA5050. The Positive-going edge of every second clock pulse is nominally in the centre of each remote control data bit (Fig.8).

12 GLR General line reset

This input signal from the SAA5020 Timing Chain is required for internal synchronisation of remote control data signals. 13. DEW Data entry window This input signal from the SAA5020 Timing Chain is required to reset the internal ROM row address counter prior to the display period. It is also used internally to derive the.’flash’ period. we Mullard | mee

SAAS5O50 SERIES | | APPLICATION DATA (continued) 14. CRS Character rounding select This input signal from the SAA5020 Timing Chain is required for correct character rounding of displayed characters. (Normal height characters only). 15. BCS Big character select This input from the SAA5040 Teletext Acquisition and Control device allows selection of large characters by remote control. 16. TLC Transmitted large characters This output to the SAA5020 Timing Chain enables double height characters to be displayed as a result of control characters stored in the page memory. 18. Vpp + 5 V supply This is the power supply input to the circuit. 19. TRE This input is a 6 MHz signal from the SAA5020 Timing Chain used as a character dot rate clock. 20, Fl This input is a 1 MHz equal mark/space ratio signal from the SAA5020 Timing Chain. It is used to latch the 7-bit parallel character data into the input latches. It is also used to synchron- ise an internal divide-by 6 counter. The F1 signal is internally synchronised with TR6. 21. Y Output This is a video output signal which is active in the HIGH state containing character dot information for tv display. The output is an open drain transistor capable of sinking current to Vsg 22,23, B,G,R outputs 24. These are the Blue, Green and Red Character video outputs to the tv display circuits. They are active HIGH and contain both character and background colour information. The outputs are open drain transistors capable of sinking current to Vss. 25. BLAN Blanking This active HIGH output signal provides tv picture video blanking. It is active for the duration of a box when Picture On and Display Enable are HIGH. It is also activated permanently for normal teletext display when no tv picture is required (PO LOW). The output is an open drain transistor capable of sinking current to Vgg. Full details given in Table 3. 26. LOSE Load output shift register enable This input signal from the SAA5020 Timing Chain resets the internal control character flip-flops prior to the start of each display line. This signal also defines the character display period. 27. PO Picture On This input signal from the SAA5040 Teletext Acquisition and Control device is used to control the character video and blanking outputs. When PO is HIGH, only text in boxes is displayed unless in superimpose mode. The input is HIGH for tv picture video on, LOW for picture off. See Table 3. 28. DE Display enable This input signal from the SAA5040 Teletext Acquisition and Control device is used to enable the teletext display. The input is HIGH for teletext display enabled. LOW for display cancelled. See Table 3. “ee | Mullard Uu

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Teletext character generator circuit SAA5050 SERIES TABLE 1 Character data input decoding D&Ob8a =| *5 [8 | Ps Poof te [| BSBA o [1 [etm |alsle|s fete]? tn] rebel © | ww] we*)/Q) 00] 1/8) o!c| eo n jojo) + | eee \\otRea a0 16) A) @)) iG (a)! - | | of fxfo} 2 sca aval O10), 5)/e|a)6\\0 mi pe > |e ses] lm a'nje\\2 n | Pepe] + | a” (Ssees|) 6) wl] ))00| eo] ea! n PIO) § lgenta agente a0 ao ela Oe n lols |sjo} 6 pie on 2] | 6 (2) "x an Ppp] > | a) Siete) 2) A] (1 A} ||) a Hope] | rosn |e’ |)! Cg) ite (5)! (adj | 4x 4X | | TBP) 2 | see 8) 2] 60 ae "J0}1}0} 10] ene Box Seems | OX) | 8] EJ! OB} (] Zl] | ed Np) fbn} esc® |) CM) OR) | 3] (| OH) ae x 1} Jojo) 12 Neg sion i | (i) a HHPPI % | 50" fete) 6) 8] 6D) C2 a i BPP | so” | ges] a! ws 6] | a Control characters shown in columns 0 and 1 are normally displayed as spaces. The SAAS050 character set is shown as example. Details of character sets are given in Figs. 11 to 18. * — These control characters [| are reserved for compatability Codes may be refered Character rectangle with other data codes. to by their column and ** These contro! characters row e.g, 2/5 refers to % Black represents display colour. are presumed before each row begins. White represents background. . July 1982 U Mullard ]

SAA5050 SERIES | | TABLE 2 Remote control command codes used in the SAA5050 CODE COMMAND FUNCTION b7 bg bs by bg b2 b1 oO xX X X X xX xX “tv’ mode Allows text on top row of display only. 1X X X X X X ‘Text’ mode Allows text throughout display period. 101 71 1 21 «0 Superimpose Sets Superimpose made. 1031 77 1% «4 ~21 teletext Resets Superimpose mode. Oo xX X KX X KX XxX “tv’ mode Resets Superimpose mode. 11 =X X X X X viewdata mode Resets Superimpose mode; 1X 00 1 1 0 Reveal Reveals for time-out (notes 3, 4). 1 x 0 1 0 1t 1 Reveal set Sets Reveal mode (note 3). Any command apart from reveal set. Resets Reveal mode (note 3) X = Don’t care. Notes 1. When the power is applied the SAA5050 is set into the ‘tv’ mode and reset out of Superimpose and Reveal modes. 2. ‘Text’ mode is selected when SI (pin 2) is held LOW 3. Reveal mode allows display of text previously concealed by ‘conceal display’ control characters. 4. This code is sent from the SAASO10 or the SAA5012 Series as a repeated command. Thus Reveal mode is set for as long as the Reveal key is depressed. The SAA5050 reverts to normal ‘not Reveal’ mode 160 ms after the last Reveal command. 5. The Superimpose output is LOW only if Superimpose mode is set and the DE (display enable) input is HIGH. 6. The above table shows code required for functions specified. The SAA5010 or the SAA5O12 Series transmits and the SAASO50 requires the inverse of these codes i.e. b7 to by. The code is transmitted serially in the following order: b7 by bz bz bq bs bg. For full details of remote control data coding see the SAAS010 or the SAASO12 data sheets. mye | Mullard U

Teletext character generator circuit | SAA5050 SERIES TABLE 3 Conditions affecting display (see note 3) Inputs Control data Outputs Picture On | Display Enable | Superimpose Text Display Enabled Blanking (PO) (DE) Mode {i.e. R,G,B,Y outputs) (a) 1 () Tord 1or0 t¢) (e) (b) i) 1 1orO lord 1 1 (c) i} ie) 1or0 1or0 0 (note 2) 1 (e) 1 1 1 0 1 oO (f) 1 1 1 1 1 1 (g) 1 1 0 1 1 1 Notes 1. For tv mode (Picture On = ‘1’, Superimpose mode not allowed) rows (a), (d) and (g) of Table 3 refer to display row 0 only. For all other rows text display is disabled and Blanking = ‘0’. 2. The R, G, B outputs may contain character and background colour information. The only exception is that background colours are inhibited when Blanking = ‘0’. 3. Valid during display period only (see Fig.5) otherwise no character or background information is displayed as blanking is determined by the Picture On. (No blanking if PO = ‘1’).

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