st20-gp6 STMicroelectronics, st20-gp6 Datasheet - Page 14

• Manufacturer Part Number: st20-gp6
• Description: Gps Processor
• Manufacturer: STMicroelectronics

ST20-GP6
determines whether the accumulated carrier phase in the NCO are reset to zero automatically or
continue from their existing value. The bit allocations are given in Table 3.1.
PRNcode0-11 registers
The PRNcode0-11 registers choose the code for the particular satellite, and writing these causes a
reset to the accumulated carrier phase in the NCO for the corresponding channel, if enabled by the
DSPControl register.
The bit-fields for selecting particular GPS satellites are given in Table 3.3.
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DSPControl
Bit
1:0
2
3
PRNcode0-11
Bit
6:0
Bit field
SampleRate
NCOResetEnable
PRNDisable
Bit field
PRNcode
DSP base address + #140
DSP base address + #00 to #2C
Function
Satellite code as a 7-bit value.
Table 3.2 PRNcode0-11 register format
Function
These bits control the sampling rate (the rate at which data is sent to the DMA
controller). The encoding of these bits is as follows:
When set to 1, the accumulated NCO phase for a channel is reset when the cor-
responding PRN code register is written.
When set to 1, all PRN generators are disabled.
Table 3.1 DSPControl register format
SampleRate[1:0]
00
01
10
11
Transfer period
840 s
970 s
31 s
62 s
No. of samples
accumulated
256
256
16
8
Mode
Tracking
Acquisition
Write only
Write only