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7: 12-Channel Correlator
86 GP4020 GPS Baseband Processor Design Manual
Bit
No.
Mnemonic Description Reset
Value
R/W
0
CARRIER_MIX
_DISABLE
'1' = Disable Carrier mixers (Note 1).
'0' = Enable Carrier mixers.
0W
Table 7.37 CORR SYSTEM_SETUP Register
Note 1: Disable carrier mixers by driving a fixed '+1' level on the carrier DCO port on all channel carrier mixers, so
that input mixer data is passed unaltered to the following code mixers.
7.6.32 TEST_CONTROL Register - Write Address Offset 0x1F0
This register is used to enable various test modes within the 12-channel correlator.
Bit
No.
Mnemonic Description
Reset
Value
R/W
15:12
Not used
-W
11:9 PATH_SEL[2:0]
To allow for simple factory testing of the chip, the 12-channel correlator
contains four separate scan paths, one for each of the major counters in
the chip. Only one of these paths may be enabled at any time and the
scan path to be used is selected via the PATH_SEL[2:0] bits as follows:
'000' = Not used
'001' = ACCUM_INT Counter
'010' = TIC Counter
'011' = 100KHz Output Counter
'100' = Raw_Timemark Pulse Width Counter
'1X1' = Not Used
'11X' = Not Used
000 W
8 EN_SCAN_PATH '1' = Enable Scan Test
'0' = Disable Scan Test
When Scan Test is enabled:
DISCIP1 (GPIO[4]) becomes SCAN_IN;
DISCOP becomes SCAN_OUT;
MULTI_FNIO becomes SCANCLK;
DISCIO becomes SCANSEL;
(See Note 1)
0W
7
Not used
-W
6 TEST_CACODES Allows checking of PROMPT C/A codes from all channels, 0 to 11.
Inverted PROMPT codes for channels 11:0 available on Data bus bits
[11:0], and data also seen in parallel by a read to any CH6 to CH11 read
address.
'1' = enable C/A code test
'0' = disable C/A code test
0W
5 TEST_DATA This bit sets the sign of the modulation of the test data generated when
TEST_SOURCE is set.
0W
4 TEST_SOURCE '0' = Enable self-test generator
'1' = Disable self-test generator
(See Note 2)
0W