This is a memory test utility I wrote for the JX10 / MKS70 assigner that is burned into a ROM and put into the assigner. It is also known as “MCK70” also supplied by Plasma Music. You can buy this ready programmed chip from me, or give me a small donation in exchange for the bin file to program your own 27C256 ROM.
Functionally, it initialises the memory to zero then cycles a series of tests through each section of memory that spans Gate Array, Static RAM and Cartridge port. It drives the display too, showing progress and proving that element out as well.
It has been found that when replacing the battery on a Vecoven PWM ROM version of code, that this utility is best run to correctly default all memeory locations. The code space is so tight for the ROM version of PWM, that it doesn’t have any built in initialisation or parameter checking. The SuperJX FLash however has everything needed.
It is a useful tool for fixing SuperJX assigner boards:
1. Thoroughly test the processing system memory and gate array configuration.
2. Test cartridge reliability & performance.
3. Clear all memory used for settings to zero in order to remove any undefined behaviour of application software because of out of range settings after changing the battery, replacing memory devices or performing a firmware upgrade.
Memory Tests
| Gate Array Config 2 | 1100-114C | Configuration table 2 in IC2 |
| Gate Array Config 1 | 1000-10FF | Configuration table 1 in IC2 |
| RAM Not Write Protected | 7800-7FFF | Static RAM IC5 working RAM for application firmware |
| RAM Write Protected | 6000-77FF | Static RAM IC5 controlled by write protect switch |
| RAM Shared | 1200-17FF | Shared memory in IC3 between custom chip IC2 & CPU IC8 |
| Cartridge M16C RAM | 2000-27FF | Socket CN9 |
| Cartridge M64C RAM | 2000-3FFF | Socket CN9 |
Testing these regions also tests the functionality of IC17, CPU IC8 and miscellaneous logic including write protect switch functions.
If memory settings of the instrument need to be preserved, ensure that write protect is “on”.
Same philosophy applies to the cartridge, but if the cartridge memory needs to be preserved, it is best not to have it installed in first place. It cannot test a cartidge interface wiout it being unprotected.
This software allows testing of the write protect logic and switch on the cartridge, if write protect is on or cartridge is missing, then errors will be shown for those tests.
The software has counters to monitor the number of memory test passes and failures that are displayed for each memory range. This enables the software to be run continuously for soak testing especially for example when the instrument warms up and failures can reveal themselves.
Testing shared memory can reveal faults with either the memory chip IC3 or Gate Array IC2 but first confirm that Gate Array Congi 2 & 1 areas do not reveal errors. In some situations, many errors can be generated when the configuration is not loaded correctly due to open circuit traces between processing system and gate array.
Screen Display
Start up banner
“SUPER-JX MEMORY TEST & FORMAT V1”
“(C)GWILKINSON SUPERSYNTHPROJECTS”
Each memory test phase appears in order as shown below:
- “GARRAY CFG2 1100-114C P:xx E:xx”
- “GARRAY CFG1 1000-10FF P:xx E:xx”
- “RAM NORM 7800-7FFF P:xx E:xx”
- “RAM WR PROT 6000-77FF P:xx E:xx”
- “RAM G ARRAY 1200-17FF P:xx E:xx”
- “RAM M16C 2000-27FF P:xx E:xx”
- “RAM M64C 2000-3FFF P:xx E:xx”
Counters are displayed in hexadecimal as follows, when a counter reaches “FF” it stops:
- “P:xx” – shows number of test passes
- “E:xx” – shows number of test failures
When a test has completed, the counters are replaced with a notification showing number of passes so far as: “PASSES:xx”
If an error is found then it pauses at the first location the error was discovered and the display below shows for 3 seconds before moving on to the next test:
- “A:xxxx W:xx R:xx ERRORS:xx”
A – Address Written to
W – Data that was written
R – data that was read back
ERRORS – number of errors found so far since power on
Video
Here is a video of the Test utility in action on an MKS70 with an original display on my Google Drive resource:
You must be logged in to post a comment.