Sega Mega-CD - Page 40

26. WORD DRAM TO VRAM DMA ERROR
DMA from the word RAM to the VRAM is not performed normally.
* PERIPHERAL IC
27. PCM RAM R/W ERROR
The R/W of the PCM RAM (IC13, IC14) cannot be done.
28. BACKUP RAM R/W ERROR
The backup data is destroyed.
(IClO check. The first time results in error.)
29. BACKUP RAM R/W ERROR
The R/W of the backup RAM (IClO) is not done normally.
* CD INTERFACE PART
30. CD-DRIVE NOT READY
Critical error occurred at CD-DRIVE.
31. SUB-CODE READ ERROR
The CD drive cannot read SUB-CODE (CD data).
* CD-DATA READ CHECK
32. CDC SUB-CPU READ ERROR
CD-DATA cannot be read from SUB-CPU (ICl).
33. CDC MAIN READ ERROR
CD-DATA cannot be read from the main side (mega drive side).
34. CDC - > PROGRAM RAM DMA ERROR
DMA is not performed normally from CDC (IC15) to the program
RAM (IC15 to 8).
35. CDC -> PCM RAM DMA ERROR
DMA is not performed normally from CDC (IC15) to the PCM
RAM (IC14, IC15).
36. CDC -> WORD RAM DMA ERROR
DMA is not performed from the CDC (IC15) to the word RAM
( ICll, IC12).
* DMA (DIRECT MEMORY ACCESS)
Data transfer shall be done directly by the hardware
function without going through the CPU.
The G/A (IC2) and the IC of the Mega Drive side have
this function of ·the data transfer.
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