Lexicon 200, Руководство по обслуживанию, Страница: 27 / 90

Lexicon
5-7
register, and then restoring the value when it's done. The entire contents of the SRAM is tested by writing
00 hex (00000000 binary), and verified by reading the same value back from each memory location. This
write/read sequence is also performed using the following patterns: 55 hex (01010101 binary), AA hex
(10101010 binary) and FF hex (11111111 binary).
This test was included in the Extended Diagnostics for troubleshooting purposes.
Before the test is executed, the following test code will be displayed on the Diagnostic LEDs, along with the
test number on the 7-segment display:
Test # Test Name Diagnostic LED
7-segment
display
2 SRAM COMPRESSOR “–10dB” 2
Pressing the Load button will execute the test.
Pressing the Tap/Cancel button will run the test continuously.
When the test is executed, the leftmost digit of the 7-segment display will display an “r” to indicate the test is
running. The pass/fail status of the test is displayed on the 7-segment display and front panel LEVEL LEDs.
If the test passed, the (Green) LEVEL -30dB LEDs will light.
If the test failed, the (Red) LEVEL LEDs will light.
Lexichip3 WCS Test (3)
This is the same test that resides in the power up diagnostics. It was included in the Extended Diagnostics
for troubleshooting purposes.
This test will check the program memory space (the writeable control store) of the Lexichip3. The
RAM (memory space) is first filled with the value 55 hex (01010101 binary), then each memory
location is read to see if it contains 55. If 55 is in the memory location, the location is filled with AA
hex (10101010 binary), and the next location is processed. Once the RAM has been checked for
55's and filled with AA's, the process is then repeated checking for AA's and storing 0's into
memory. Following this test is an Address test to verify all the address lines are active. Finally, the
memory is checked for 0's.
Before the test is executed, the following test code will be displayed on the Diagnostic LEDs, along with the
test number on the 7-segment display:
Test
# Test Name Diagnostic LED
7-segment
display
3 Lexichip3 WCS COMPRESSOR “–3dB” 3
Pressing the Load button will execute the test.
Pressing the Tap/Cancel button will run the test continuously.
When the test is executed, the leftmost 7-segment display will display an “r” to indicate the test is running.
The pass/fail status of the test is displayed on the 7-segment displays and front panel LEVEL LEDs.
If the test passed, the (Green) LEVEL -30dB LEDs will light.