emusonacid!

Boot prom 'tests' as described in the EOS TSM (for all E4 series modules)

All LEDs are turned on at power up and are turned off when a test successfully passes

E4 classic (not ultra):
1. Master LED off = cpu running
2. Preset manage LED off = 68901 multifunction periperal tests OK
3. Preset Edit LED off = read/write to LCD OK
4. Message on LCD = everything is OK (from the perspective of the PROM code)


E4 Ultra:
1. Master LED off = cpu running
2. Preset Manage LED off = DRAM OK
3. Preset Edit LED off = FPGA access OK
4. Disk LED off = G-chip registers OK
5. Sample Manage LED off = FPGA register access OK
* will enter a looping 'bus test' if this fails -> exercise address and data pins (& buffered copies) so they can be 'scoped
6. Sample Edit off = writes to LCD
7. MIDI LED off = K-chip registers OK
8. All LEDs off = everything OK (from the perspective of the PROM code)

Next the PROM code checks for the presence of a FLOPPY, checks whether EOS is on FLASH & boots it (otherwise tries to load from floppy)


Happy troubleshooting