Graphics Chip Blit; Error Codes Quick Reference - Atari 520STE Field Service Manual

has been found to be more effective than the DMA test for some types of failures; these
show up as "Data Compare" errors.
The test program will save the data on the cylinder used for testing and restore the data
when the test is done (when "quit" or "park heads" is selected).
NOTE. Always back up the hard disk before running this test. Bad hardware can still
destroy the data on the disk.
The test will run until the operator presses the (Esc) key. There is no "Pass" condition. A
failure will usually show up within a few seconds if it is going to occur at all. The following
messages can appear if there is an error:
Controller Not Responding There is no communication between the computer and hard
disk. Cycling power on the hard disk may correct this condition.
Operation Timed Out The computer sent a command, which was accepted by the hard
disk, but the hard disk did not return a completion code in time.
Command Error The hard disk attempted to execute a command, but an error occurred in
the hard disk.
DMA Count Error After completing a data transfer, the byte count of the data in the
computer memory controller was incorrect.
Data Compare Error This is followed by the data written to the disk and the data read from
the disk. The error is the condition this test was meant to detect. The circuitry involves the
custom LSI chips (GSTMCU, Memory Controller, and DMA Controller). The comparison is
done by the CPU, and it has found an error in the read/write buffers in memory.
3.20 GRAPHICS CHIP BLiT (G,Y)
Two tests are available for this chip. The "Short BLiT Test" checks the ability of the
BLiTTER to move blocks of memory around and perform logical operations on the
data. No patterns appear on the screen. If an error is detected, one of the error
codes (G1–G12) is displayed.
In the "Long BLiT Test", a triangle is drawn on the screen and rotated 180 degrees
until a rectangle is formed. If a color monitor is used, two identical images will be
drawn. If an error occurs, a message will appear telling you to replace the BLiTTER.
Corrective action for any error is the same:
a. Verify the jumpers for the BLiT chip are installed correctly.
b. Replace the chip (and if that does not cure the problem, replace the 68000).

3.21 ERROR CODES QUICK REFERENCE

This is a brief summary of all error codes which may occur when running the
diagnostic.
3.21.1 Initialization
Error occuring before the title and menu appear. (see section 3.5.1)
I1 RAM data line is stuck.
I2 RAM disturbance. Location is altered by write to another location.
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