
31
TABLE 13. WAIT THRESHOLD/DECREMENT VALUE REGISTER (IWA = *00Ch)
P(15:0)
FUNCTION
31
μ
PTestBit. This bit is provided as a microprocessor controlled condition code for the filter compute engine for conditional execution
or synchronous startup. Active high.
30
Set to 0.
29:20
Decrement value 1. Positive number.
19:10
Decrement value 0. Positive number. Usually set equal to the Threshold (bits 9:0).
9:0
Threshold. Number of samples needed to run a filter set and produce an output.
TABLE 14. RESET WRITE POINTER OFFSET REGISTER (IWA = *00Dh)
P(15:0)
FUNCTION
8:0
This parameter is the offset between filter compute engine read and write pointers on filter compute engine reset. On reset, the read
and write pointers for all the filters are loaded, the read pointer with zero and the write pointer with this value. Set to zero for a single
filter and two for a multi-filter chain.
TABLE 15. AGC GAIN LOAD REGISTER (IWA = *00Eh)
P(15:0)
FUNCTION
15:0
This location loads the AGC accumulator. If the loop attack/decay gain is set to zero and this value is within the AGC gain limits, the
AGC will hold this value. If not, the AGC will be set to this gain (or to a limit) and then start to settle.
4xE (15:12), 12xM, (11:0)
TABLE 16. AGC GAIN READ STROBE REGISTER (IWA = *00Fh)
P(15:0)
FUNCTION
31:0
for RD;
N/A for WR
Writing to this location will sample the AGC loop filter output (forward gain value) to stabilize it for reading. The value is read from
this location after waiting the 4 clocks required for read synchronization.
31:16
15:0
AGC Gain for Channel 1.
AGC Gain for Channel 0.
TABLE 17. AGC LOOP ATTACK/DECAY GAIN VALUES REGISTER (IWA = *010h)
P(15:0)
FUNCTION
31:24
Loop gain 0, decay gain value (signal decay, increase gain) 31:28 = EEEE (exponent), 27:24 = MMMM (mantissa)
23:16
Loop gain 1, decay gain value 23:20 = EEEE (exponent), 19:16 = MMMM (mantissa)
15:8
Loop gain 0, attack gain value (signal arrival, decrease gain) 15:12 = EEEE (exponent), 11:8 = MMMM (mantissa)
7:0
Loop gain 1, attack gain value 7:4 = EEEE (exponent), 3:0 = MMMM (mantissa)
TABLE 18. AGC GAIN LIMITS REGISTER (IWA = *011h)
P(15:0)
FUNCTION
31:16
Upper gain limit. See AGC section.
15:0
Lower gain limit. See AGC section.
TABLE 19. AGC THRESHOLD REGISTER (IWA = *012h)
P(15:0)
FUNCTION
15:0
AGC threshold. Equals 1.64676 times the desired magnitude of the I1/Q1 output.
HSP50216