Wcs Test; Wc Test:; Int Test; Adf Test - Lexicon MPX 500 Service Manual

Lexicon
If what is written to all locations is read back, the test will pass.

#3 WCS Test:

This test will verify the program memory space of the Lexichip 3. The Ram (memory space) is first filled with
the value 55hex (01010101 binary), then each memory location is read back to confirm it contains the 55.
The memory space is then filled with AAhex (10101010 binary) and the memory is read back again. The
final test is the memory is filled with 0s. If what is written to all locations is read back, the test will pass.

#4 INT Test:

This test will verify that the Lexichip 3 interrupt (INT/) is working and occurring at the proper time intervals.
The Lexichip 3 does this by providing this signal to the Z80's maskable interrupt line. If the Z80 sees the
signal at the proper times the test will pass.

#5 ADF Test:

This test will verify that the Audio Data File in the Lexichip 3 is working properly. The Lexichip 3 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.

#6 EEPROM Test:

This test has 2 parts that will verify the functions of the EEPROM in the MPX 500. The EEPROM will be
initialized if either of the two parts of the test fail.
The First part of the 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 Second part of the test will 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. Then the stored value is
verified 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.

#7 DRAM Test:

The Z80 performs two tests to verify the DRAM, a Data test and an Address test.
In the Data test, the Z80 writes AA (hex) (10101010) into all of the memory locations then reads them back
to check them. It repeats the process with 55 (01010101).
The Address test, the Z80 writes a count into the memory then reads it back (i.e. 00000001, 00000010,
00000011). This test will take approximately 45 seconds to complete.

#8 Switch Test:

The Switch Test diagnostics has two tests. The tests verify the operation of the Front panel switches (7)
and Footswitches (2) along with their associated LEDs at the same time. The LCD Display will also indicate
the name of the switch being pressed & held.

Footswitches:

To perform this test, a Dual stereo style footswitch must be plugged into the Footswitch jack on the back of
the MPX 500 using a ¼" tip/ring/sleeve cable.
Press the LEFT FOOTSWITCH (Ring). The BYPASS LED will light and the LCD Display will indicate
5-5