Lexichip3 Audio Data File Test (5); Eeprom Checksum (8) - Lexicon MPX 110 Service Manual

MPX 110 Service Manual

LEXICHIP3 AUDIO DATA FILE TEST (5)

The Audio Data File (ADF) is a fast synchronous 128-word SRAM that provides audio data buffering and
storage for: external memory references, Serial I/O, and the Host-to-Lexichip data port. ADF locations also
function as ARU Registers and as scratchpad memory. This test will verify that the Lexichip3 Audio Data
File is working properly.
Before the test is executed, a test code will be put out on the Binary LED's. The code is:
Edit Bypass
O O
MSB
If a failure occurs, the Clip (red) headroom LED's will be turned on in addition to the binary code.
If the BYPASS button is pressed, the failure is ignored and the next test will be executed.
If the TAP button is pressed, the CPU will attempt to go into a mode where it can execute the test
continuously.

EEPROM CHECKSUM (8)

This test will read each byte in the User Register portion of the EEPROM and add them together to
calculate a checksum. This value is compared with the checksum value stored in the EEPROM itself. This
checksum will be recalculated each time a register is stored.
The test will also verify that the EEPROM has been initialized properly. This is done by storing the software
version of the EPROM in the first five bytes of the EEPROM, and then verifying the stored value is correct
when the test is executed. If the stored value read from the first five bytes of the EEPROM is incorrect, the
EEPROM will be initialized.
Before the test is executed, a test code will be put out on the Binary LED's. The code is:
Edit Bypass
O O
MSB
If a failure occurs, the Clip (red) headroom LED's will be turned on in addition to the binary code.
If the BYPASS button is pressed, the failure is ignored and the next test will be executed.
If the TAP button is pressed, the CPU will attempt to go into a mode where it can execute the test
continuously.
5-4
Store Tap
l
O
LSB
Store Tap
l
O
LSB