41CL: Plugging a Module from RAM rather than FLASH?

[Monte Dalrymple]

(11-02-2018 06:47 PM)burkhard Wrote:  QUESTIONS
a. Is the basic idea of plugging a ROM into the MMU from RAM rather than FLASH a sound one?
b. Did I do some procedural error?
c. Why is the CRC of the file that left the PC correct, but that stored in RAM not? I know a page of "00" yields a different CRC than a page of "FF". Should I have "initialized" the RAM with all FF or something like that before the XEQ YIMP? (rationale: I'm not sure if YIMP takes everything or just what isn't empty so maybe starting with all FF is better).
d. Why did subsequent re-attempts yield an immediate "OVERRUN" displayed on the 41CL?
e. How do I recover from these persistent OVERRUNs?

Thanks!

a. Yes, I debug this way all the time.
b. No, everything looks right. You need to be running in Turbo50 to keep up with
the serial data.
c. Something went wrong somewhere in the transfer. That's what the CRC error
is telling you. No need to initialize the RAM before YIMP if you are transferring
the entire 8k bytes.
d. Something went wrong with the serial transfer and there is a latched overrun
condition.
e. SERINI will clear the latched error condition, but you'll also need to redo the
baud selection after that command.