Cirrus Logic CDB5529 - Manual (Page 12)

CDB5529
12 DS246DB1
Trouble Shooting the Evaluation Board
This section describes special test modes incorporated
in the microcontroller software to diagnose hardware
problems with the evaluation board.
Note: To enter these modes, set the test switches to the
appropriate position and reset the evaluation board. To re-
enter the normal operation mode, set the switches back to
binary zero and reset the board again.
Test Mode 0, Normal Mode: This is the default
mode of operation. To enter this mode, set the test
switches to 000 and reset the board. The evaluation
board allows normal read/writes to the ADC’s reg-
isters. All the LED’s toggle on then off after reset,
and then only when communicating with the PC.
Test Mode 1, Loop Back Test: This test mode
checks the microcontroller’s on-chip UART. To
enter this mode, set test switches to 001, set HDR7
for loop back, and then reset the board. If the com-
munication works, all the LED's toggle. Other-
wise, only 1/2 of the LED’s toggle to indicate a
communication problem.
Test Mode 2, Read/Write to ADC: This test mode
tests the microcontroller’s ability to read and write
to the ADC. To enter this mode, set the switches to
010 and reset the board. In this test mode, the
ADC’s configuration, offset, and gain registers are
written to and then read from. If the correct data is
read back, all the LED's toggle. Otherwise, only
half of them toggle to indicate an error.
Test Mode 3, Continuously Acquire Single Con-
version: This test mode repetitively acquires a sin-
gle conversion. To enter this mode, set the test
switches to 011 and press reset. A binary three is in-
dicated on the LED’s. By probing HDR6 and using
CS as a triggering pin, an oscilloscope or logic an-
alyzer will display in real-time how the microcon-
troller reads conversion data.
Test Mode 4: Reserved for future modifications.
Test Mode 5, Continuously Read Gain Register:
This test mode repetitively acquires the gain regis-
ters default contents (0x400000 HEX). To enter
this mode, set the test switches to 101 and press re-
set. The LED’s should indicate a binary five. By
probing HDR6 and using CS as a triggering pin, an
oscilloscope or logic analyzer will display in real-
time how the microcontroller acquires a conver-
sion.
Test Mode 6, PC to Microcontroller RS-232
Communication Link Test: This test mode tests
the ability of the PC to communicate to the evalua-
tion board. It consists of two subtests: 1) test the
link between the PC and the RS-232 interface cir-
cuitry; and 2) test the RS-232 link between the PC
and the microcontroller. HDR7 distinguishes these
two subtests. Set HDR7 to Normal to test the com-
plete communication link. Or set HDR7 to Loop
Back to test the link between the RS-232 Circuitry
and the PC. Then, set the test switches to 110 and
reset the evaluation board. The LED’s should indi-
cate a binary six signifying that the hardware is
ready to initiate the test. To complete the test, the
user must initialize the PC. First, use the SETUP
menu to select a communications port and then se-
lect the TESTRS232 option. From there, user
prompts navigate the user through the test. The PC
indicates if the test passes or fails. Once either test
is complete, the LED’s toggle to indicate that the
test mode is complete.
Test Mode 7, Toggle LED’s: This test mode tests
the evaluation board LED’s. To enter this mode,
set the test switches to 111 and reset the board. If
the mode passes, the LED’s toggle.
Note: Remember, to return to the normal operating
mode, set the test switches to binary zero, return HDR7
to Normal, and reset the evaluation board.