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 processor

" 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

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

SA20552 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

Pentara Plus (5th Generation)

256k (4x 64k 27512) MAIN S/w

8k (SEEQ 52B33) bt arc test

32K STATIC RAM (4x 8k TOSHIBA TC5565APL-12)

8k eeprom (1 x SEEQ DQ52B33)