VFX Article, Chapter 6

6. Program 4, Test mode

This program can be used during hardware checkout to isolate problems with your VFX board. It is activated by setting the dip switch as follows, SW1-1:ON, SW1-2:OFF, SW1-3:OFF, SW1-4:ON and pressing the reset button. The test mode individually tests the system RAM, the Codec and the LED display. In this mode the external SRAM is constantly written and read and the number of errors are displayed on the LED. If the LED display is blank and all the power supplies are normal, then there is something wrong with the LED or the driver. If the LED has a number other than zero then there probably is a problem with the SRAM. The CODEC data is received and immediately re-transmitted. Thus, the microphone input is echoed back the headphones. If there is no output or if the output doesn't sound like the input then there is a problem. If there are no other fault indications and the microphone and speaker are working then there is a probably problem with the CODEC. If nothing happens at all and the power supplies are normal then there may be a problem with the ADSP-2105 or the EPROM.

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