CDB5521/22/23/24/28
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Test Mode 3, Continuously Acquire Single
Conversion
2) test the RS-232 link between the PC and the
microcontroller.
This test mode repetitively acquires a single
conversion. To enter this mode, set the test
switches to 011 and press reset. A binary three
is indicated on the LED’s. By probing HDR6
and using CS as a triggering pin, an oscillo-
scope or logic analyzer will display in real-time
how the microcontroller reads conversion data.
HDR7 distinguishes these two subtests. Set
HDR7 to Normal to test the complete commu-
nication 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 select 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 com-
plete.
•
•
Test Mode 4
Reserved for future modifications.
Test Mode 5, Continuously Read Gain Reg-
ister
This test mode repetitively acquires the gain
registers default contents (0x800000 HEX). To
enter this mode, set the test switches to 101 and
press reset. The LED’s should indicate a binary
five. By probing HDR6 and using CS as a trig-
gering pin, an oscilloscope or logic analyzer
will display in real-time how the microcontrol-
ler acquires a conversion.
•
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.
•
Test Mode 6, PC to Microcontroller RS-232
Communication Link Test
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.
This test mode tests the ability of the PC to
communicate to the evaluation board. It con-
sists of two subtests:
1) test the link between the PC and the RS-232
interface circuitry; and
20
DS317DB2
CIRRUS [ CIRRUS LOGIC ]
