> Yes, for that you need flow control. For example, you you have the
> programmer return the amount of bytes free in the buffer after each
> command stream you send to the device.
>
For a moment i was adding a "return bytes free in buffer" command to
the protocol, but then i realized that if the code sent that command
as the last in command stream, and waited for the answer, the answer
would always be that the buffer is empty, because it just had to go
though all the data in the buffer to get the command. So i'm sticking
with the
- query buffer size in the beginning
- when doing opbuf writes, count bytes sent
- if about to have sent too many bytes, instead send NOP and wait for
the ACK and clear the counter and continue
I have the protocol specification ready and the AVR code compiles
already, i'm just moving to flashrom code. I'll attach the .txt to
this mail, it's better viewed with proper tabs and fixed-width font
(leafpad fullscreen 1280x1024 is nice :P).
--
urjaman
Serial Flasher Protocol Specification
Command And Answer Sequence - not all commands give an answer
PC: LENGHT(8bit) COMMAND(8bit) <LENGHT PARAMETER BYTES>
DEV: ACK/NAK(8bit) <OPTIONAL RETURN BYTES (only if ACK)> or nothing
ACK = 0xAA
NAK = 0x55
All multibyte values are little-endian.
COMMAND Description Parameters Return
Value
0x00 NOP none ACK
0x01 Query serial buffer size none ACK +
16bit size / NAK
0x02 Query supported bustypes none ACK +
8-bit flags (as per flashrom) / NAK:
bit 0:
PARALLEL
bit 1:
LPC
bit 2:
FWH
bit 3:
SPI if ever supported
0x03 Query supported chip size none ACK +
8bit power of two / NAK
0x04 Query operation buffer size none ACK +
16bit size / NAK
0x05 Read byte 24-bit addr ACK +
BYTE / NAK
0x06 Read n bytes 24-bit addr + 24-bit lenght ACK +
lenght bytes / NAK
0x07 Initialize operation buffer none ACK /
NAK
0x08 Write to opbuf: Write byte 24-bit addr + 8-bit byte nothing
/ NAK (NOTE: takes 6 bytes in opbuf)
0x09 Write to opbuf: Write byte seq 8-bit byte nothing
/ NAK (NOTE: takes 1 bytes in opbuf)
0x0A Write to opbuf: delay 32-bit usecs nothing
/ NAK (NOTE: takes 5 bytes in opbuf)
0x0B Execute operation buffer none ACK /
NAK
- Execute operation buffer will also clear it
0x?? unimplemented command any NAK
--
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