No errors and AtoMMC is the stil working. Re-inserting SD card dos not fix the problem.
It's a very weird problem, the atom has always worked with the RAMROM loader till now.
Erik
No errors and AtoMMC is the stil working. Re-inserting SD card dos not fix the problem.
Sorry, we are talking at cross purposes.
Code: Select all
<Press BREAK>
*CWD SYS
*LOAD TEST
LINK #2800
Code: Select all
*HELP
*CAT
*LOAD TEST
OK, so what's changed then?
Here are the results:hoglet wrote: ↑Wed Mar 20, 2024 8:14 pmSorry, we are talking at cross purposes.
Can you get it into the broken state:Then try some more commands, for example:Code: Select all
<Press BREAK> *CWD SYS *LOAD TEST LINK #2800
I want to see what errors are generated in the broke state.Code: Select all
*HELP *CAT *LOAD TEST
OK, so what's changed then?
Dave
All * commands are falling with ERROR 224 which is a nice clue.
Code: Select all
<Press BREAK>
PRINT &!#E0DE, &?#BFFE'
*CWD SYS
*LOAD TEST
PRINT &!#E0DE, &?#BFFE'
LINK #2800
PRINT &!#E0DE, &?#BFFE'
*HELP
PRINT &!#E0DE, &?#BFFE'
Don't be sorry Dave I am learning a lot, here is the result of all that typinghoglet wrote: ↑Thu Mar 21, 2024 5:04 pmAll * commands are falling with ERROR 224 which is a nice clue.
Errors on the Atom are generated by BRK instructions, and error number is the 2 + the LSB of the address of the BRK. So ERROR 224 means a BRK instruction has been hit at address xxDE.
Now, the default OSCLI vector (for executing star commands) when AtoMMC is running is #E0DE.
So it looks like for some reason the AtoMMC ROM at #E000 has be switched out.
Could you run the following test:(Sorry for so much typing, but we are getting closer)Code: Select all
<Press BREAK> PRINT &!#E0DE, &?#BFFE' *CWD SYS *LOAD TEST PRINT &!#E0DE, &?#BFFE' LINK #2800 PRINT &!#E0DE, &?#BFFE' *HELP PRINT &!#E0DE, &?#BFFE'
Post a screen shot of the result.
I want to see if the AtoMMC ROM at #E000 literally vanishes and is replaced by zeros, and whether this change corresponds to a change in BFFE.
Dave
Great, that shows the #E000 ROM is changing, yet BFFE is stays at 02. Which is impossible normally!
Code: Select all
DO PRINT &?#BFFE;UNTIL 0
I have checked with the multimeter en there is continuetie between pin 31 and pin 9. Also tried the code and pushed on pin 9. The result stays 2.hoglet wrote: ↑Thu Mar 21, 2024 6:12 pm
So I have a hypothesys....
I think there may be a problem with the D2 line (again) but this time on YARRB. The most likely problem is a poor joint on pin 9 of the CPLD. Or a maybe broken track between pin 9 of the CPLD and pin 31 of the 6502. Least likely (but possible) is the CPLD is damaged.
You could investigate with a multimeter, checking continuity between these two pins.
Alternatively, try running this code after power up:then gently pressing down on pin 9 with something plastic and see if the 02 changes to 06Code: Select all
DO PRINT &?#BFFE;UNTIL 0
It may be just touching pin 9 "fixes" the issue.
Dave
Probably, but I don't see how the fault you had with the Combo board would have caused this.
Code: Select all
PRINT &?#BFFE'
?#BFFE=6
PRINT &?#BFFE'
?#BFFE=7
PRINT &?#BFFE'
hoglet wrote: ↑Thu Mar 21, 2024 6:49 pmProbably, but I don't see how the fault you had with the Combo board would have caused this.
What does the following do:DaveCode: Select all
PRINT &?#BFFE' ?#BFFE=6 PRINT &?#BFFE' ?#BFFE=7 PRINT &?#BFFE'
Code: Select all
PRINT &!#E0DE,&?#BFFE'
?#BFFE=6
PRINT &!#E0DE,&?#BFFE'
?#BFFE=2
PRINT &!#E0DE,&?#BFFE'
hoglet wrote: ↑Thu Mar 21, 2024 7:06 pm OK, one last test before I give up on the CPLD:(I'm trying to figure out if D2 is broken on reads, writes or both)Code: Select all
PRINT &!#E0DE,&?#BFFE' ?#BFFE=6 PRINT &!#E0DE,&?#BFFE' ?#BFFE=2 PRINT &!#E0DE,&?#BFFE'
Dave
Pin 9 is de middle pin in the picture. I wil tomorow resolder some pins to rule bad connections out.hoglet wrote: ↑Thu Mar 21, 2024 8:06 pm The power-up default for BFFE is 06 (D2=1) which selects the OS ROM Set with AtoMMC (A0D8FFA2).
But it reads back as 02 (D2=0)
Writing 06 (D2=1), shouldn't have any effect, but it does, selecting the OS ROM Set with DOS (88013600)
So regardless of what's on D2, when a write happens BFFE bit 2 in the CPLD is updated to zero.
This could be a damaged CPLD, but I still think it's more likely this is a bad joint on pin 9.
So I would second Ken's suggestion to carefully reflow that pin.
Can you post a close-up / macro photo of those pins?
Dave