6502 Processor Test

The 6502 Processor Test screen provides visual and audible information to indicate the condition of the 6502 sound microprocessor and associated circuitry. Ail functions of the sound microprocessor are checked including: RAM/ROM, interrupts, music synthesizer, and sound-effects processor. Basic communication between the T-l 1 (master) and the 6502 (slave) microprocessors is also checked.

The 6502 test starts with a reset/communications check that first resets the 6502 and then checks for proper response to start up protocol. This test checks the communications ports (T-l 1 to 6502 and 6502 to T-l 1), the 6502 reset circuit, and the general condition of the 6502.

If the 6502 circuitry does not respond properly to the reset, the system retries the reset procedure ten times. Then an error message and retry count number is displayed as shown in Figure 3-4.

If the 6502 circuitry fails to reset through al! ten attempts, -a communications error message is displayed as shown in Figure 3-5.

If the reset/communications check passes, then the condition of the 6502 microprocessor, RAM, ROM, interrupts, music (Yamaha) synthesizer, and associated cir-

6502 PROCESSOR TEST

Figure 3-4 Reset Retry

6502 PROCESSOR TEST

PRIiSS KICK Hl I I ON lOCONTIMIv

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