Processor Card

SA20001 and SA20002 were both needed

Herald A (1st Generation) c1980
At first the memory was on a separate card to the processor

At its heart a micro 

" parts of the EAROM have checksums 33 bytes at the beginning and 250 bytes near the end" (see NEWSFLASH 041)
Details of how EAROM is used to store speed dials can be found in NEWSFLASH 064)
The first 1 k of RAM 4000h-43FFh, is on the processor card
Another 2k can be found on the Extension Memory card
H3s Software reports the following RAM errors
 To (hex) Rom
 / 4000 40ff V,W,X 1ST IC16
 04100  41ff S,T,U 2ND IC25
 1 4200 42ff P,Q,R 3RD IC26
 2 4300 43ff M,N,O 4TH IC31
 3 4400 44ff J,K,L 5TH IC35
 4 4500 45ff G,H,I 6TH IC38
 5 4600 46ff D,E,F 7TH IC39
 6 4700 47ff A,B,C 8TH IC44
 7 4800 48ff   
 8 4900 49ff EAROM  
 9 4a00 4aff % first 33 bytes
 : 4b00 4bff & Final 250 bytes

Then as more memory fitted on one IC, both memory and processor could be found on the same card...

SA20550 Combined processor and Memory c1983

  • Herald (100B) B5 (2nd Generation)

24k (3 x8) Eprom 2764
6k (3x 2k) EEprom intel 2816
8k (4x2k) Static Ram + 1 F cap

SA20551 - No huge cap now - But you still need a Tones card

Herald B8 ( 3rd Genration)

In october 1984 it was announced that Herald A and B5 were due to be phased out by the end of 1984 and would be replaced by S5102  (Herald C)
See Herald Information Note 94

128k (8x27128) Eprom software
2k (eeprom) BT ARC TEST
24 k (3xhm6264lp-15) static ram
10k(5xDQ528B13-250) eeprom

Herald B8 is more or less a Pentara via upgrade
The same EProms were used, they just had to be put in different socket names


Combined processor and Memory and Tones

  • Pentara (4th Generation)
No need for Tones card any more

128 k (8x27128) Eprom Software
2k (eeprom) BT ARC TEST
24 k (3xD2186A) static ram
10k (5xDQ528B13-250 2k) eeprom


Combined processor and Memory and Tones

  • Pentara Plus (5th Generation)

256k (4x 64k 27512) MAIN S/w
8k (SEEQ 52B33) bt arc test
32K STATIC RAM (4x 8k 
8k eeprom (1 x SEEQ DQ52B33)
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