Hi David,
But nothing seems to come out. I need a scope.
It might be waiting for some sort of passkey, although this seems a little unlikely. If so, though, our only options are either hope that some nice person from Amstrad tells us what it is, or else to build a JTAG adaptor and extract the ROM...
I suspect it's more primitive than the E2's PBL so I doubt a passkey is required. Request 00 always replies with a NAK in PBL V3.1 but perhaps it does something useful in the earlier version and was changed to be a constant NAK later? Do you get anything from request 01?
PBL V3.1 Build:1277 EXP packet format ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Offset Size Value Name Description 0 1 2 stx ASCII STX byte. 1 1 0/1 comp Is `data' compressed. 2 2 - len Length of data. 4 len - data Payload. 4+len 1 - cksum Sum modulo 0x100 of bytes in len and data.
First byte of payload gives message type.
Payload requests ~~~~~~~~~~~~~~~~
Contents of data in received packet. First two bytes given request number. Reply is request_number | 0x80 if all went well, or a NAK reply otherwise.
Request: 00 Not used. Reply: 15 NAK message, sent to indicate disagreement.
Request: 01 00 Set 0x1001c = 0x01 to remember request 01 received. Reply: 81 00
Cheers,
Ralph.