Apple II Technical Notes _____________________________________________________________________________ Developer Technical Support Apple IIgs #95: ROM Diagnostic Errors Written by: Dan Strnad September 1990 This Technical Note describes errors returned by the ROM Diagnostics on Apple IIgs systems. _____________________________________________________________________________ The Built-In Diagnostics Revealed The IIgs has a self-test capability in ROM. The self-test is activated by pressing Open-Apple and Option on power up, or Open-Apple, Option, and Reset. During the test, the test number is visible on the bottom of the screen followed by six zeros. After all tests are complete, a continuous 6 KHz one- second beep sounds and the screen displays a System Good message. If any test fails, the screen displays a message of the form System Bad: AABBCCDD on the lower left hand side and a staggered AABBCCDD on the upper left hand side to help read the error code in the event of a RAM failure. In the event of video failure, the failure code is also sent to the printer port. In the number contained in the error message, AA is the test number that failed and the failure code is embedded in the BB, CC, and DD fields. The complete failure codes for each of the 12 tests are as follows: Self Test 1: ROM Test AA = 01 BB = Failed checksum DD = 01 if the test encountered bad RAM and the error code is a RAM error code similar to the RAM Test error codes For a failure in ROM, the ROM diagnostics also display RM on the top left hand corner of the screen. Self Test 2: RAM Test AA = 02 BB = Bank Number (or $FF for ADB Tool call error) CC = Bit(s) failed Self Test 3: Soft Switches and State Register Test AA = 03 BB = State Register bit (if any) CC = Low byte of soft switch address Self Test 4: RAM Address Test AA = 04 BB = Failed bank number (or $FF for ADB Tool call error) CCDD = Failed address Self Test 5: Speed Test AA = 05 BB = 01: Speed stuck slow 02: Speed stuck fast Self Test 6: Serial Test AA = 06: BB = 01: Register R/W 04: Tx Buffer empty status 05: Tx Buffer empty failure 06: All Sent Status fail 07: Rx Char available 08: Bad data Self Test 7: Clock Test AA = 07 DD = 01: Fatal error occurred and the test is aborted Self Test 8: Battery RAM Test AA = 08 BB = 01: Address test and CC = bad address 02: Non-volatile RAM failed and CC = pattern, DD = address Self Test 9: Apple Desktop Bus Test AA = 09 BBCC = Bad checksum DD = 01: Apple Desktop Bus tools call encountered a fatal error, no checksum computed. Self Test 10: Shadow Register Test AA = 0A BB = 01: Text page 1 fail 02: Text page 2 fail 03: Apple Desktop Bus Tool call error 04: Power On Clear bit error Self Test 11: Interrupts Test AA = 0B BB = 01: VBL interrupt time-out 02: VBL IRQ status fail 03: 1/4 sec interrupt 04: 1/4 sec interrupt 05: 06: VGC IRQ 07: Scan line Self Test 12: Sound Test AA = 0C DD = 01: RAM data error 02: RAM address error 03: Data register failed 04: Control register failed 05: Oscillator interrupt timeout Further Reference _____________________________________________________________________________ o Apple IIgs Hardware Reference, Second Edition