
Rev. 3.05 May 27, 1999
22
1999 National Semiconductor Corporation
FREQ_A
4B
R/W
0
7-10
7:0
Frequency word for channel A. Format is a 32-bit, 2’s complement number spread across 4
registers. The LSBs are in the lower registers. The NCO frequency F is F/F
CK
=FREQ_A/2
32
.
PHASE_A
2B
R/W
0
11-12
7:0
Phase word for channel A. Format is a 16-bit, unsigned magnitude number spread across 2
registers. The LSBs are in the lower registers. The NCO phase PHI is PHI=2*pi*PHASE_A/
2^16.
FREQ_B
4B
R/W
0
13-16
7:0
Frequency word for channel B. Format is a 32-bit, 2’s complement number spread across 4
registers. The LSBs are in the lower registers. The NCO frequency F is F/F
CK
=FREQ_B/2
32
.
PHASE_B
2B
R/W
0
17-18
7:0
Phase word for channel B. Format is a 16-bit, unsigned magnitude number spread across 2
registers. The LSBs are in the lower registers. The NCO phase PHI is PHI=2*pi*PHASE_B/
2^16.
A_SOURCE
2
R/W
0
19
1:0
0=Select
AIN
as channel input source. 1=Select
BIN.
2=3=Select TEST_REG as channel
input source.
B_SOURCE
2
R/W
1
19
2:3
0=Select
AIN
as channel input source. 1=Select
BIN.
2=3=Select TEST_REG as channel
input source.
EXP_INH
1b
R/W
0
20
0
0=Allow exponent to pass into FLOAT TO FIXED converter. 1=Force exponent in DDC chan-
nel to a 7 (maximum digital gain). This affects both channels.
AGC_FORCE
1b
R/W
1
20
1
0=Enable AGC counter operation. 1=AGC loop operates continuously regardless of
AGC_EN
pin. This affects both channels.
AGC_RESET_EN
1b
R/W
0
20
2
0=Initial condition is never used. 1=Integrator is reset each time the AGC transitions from
idle to active. This affects both channels.
AGC_HOLD_IC
1b
R/W
0
20
3
0=Normal closed-loop operation. 1=Hold integrator at initial condition. This affects both
channels.
AGC_LOOP_GAIN
2b
R/W
0
20
4:5
Bit shift value for AGC loop. Valid range is from 0 to 3. This affects both channels.
AGC_COUNT
2B
R/W
0
21-22
7:0
Counter value for AGC enable counter. Format is a 16-bit, unsigned magnitude number
spread across 2 registers. The LSBs are in the lower register. The value represents the num-
ber of CK cycles over which the loop is active.
AGC_IC_A
1B
R/W
0
23
7:0
AGC integrator initial condition for channel A. Format is an 8-bit, unsigned magnitude num-
ber. This number is written into the magnitude MSBs of the channel A AGC integrator when-
ever it is reset to the initial condition.
AGC_IC_B
1B
R/W
0
24
7:0
AGC integrator initial condition for channel B. Format is an 8-bit, unsigned magnitude num-
ber. This number is written into the magnitude MSBs of the channel B AGC integrator when-
ever it is reset to the initial condition.
AGC_RB_A
1B
R
0
25
7:0
AGC integrator readback value for channel A. Format is an 8-bit, unsigned magnitude num-
ber. The user can read the magnitude MSBs of the channel A integrator from this register.
AGC_RB_B
1B
R
0
26
7:0
AGC integrator readback value for channel B. Format is an 8-bit, unsigned magnitude num-
ber. The user can read the magnitude MSBs of the channel B integrator from this register.
TEST_REG
14b
R/W
0
27(LSBs)
28(MSBs)
7:0
5:0
Test input source. Instead of processing values from the
AIN/BIN
pins, the value from this
location is used instead. Format is 14-bit 2s complement number spread across 2 registers.
Reserved
1B
-
-
29
7:0
For future use.
Reserved
1B
-
-
30
7:0
For future use.
DEBUG_EN
1b
R/W
0
31
0
0=Normal. 1=Enables access to the internal probe points.
DEBUG_TAP
5b
R/W
0
31
1:5
Selects internal node tap for debug.
0 selects F1 output for BI, 20 bits
1 selects F1 output for BQ, 20 bits
2 selects F1 output for AQ, 20 bits
3 selects F1 output for AI, 20 bits
4 selects F1 input for BI, 20 bits
5 selects F1 input for BQ, 20 bits
6 selects F1 input for AI, 20 bits
7 selects F1 input for AQ, 20 bits
8 selects NCO A, cosine output. 17 bits, 3 LSBs are 0.
9 selects NCO A, sine output, 17 bits, 3 LSBs are 0.
10 selects NCO B, cosine output, 17 bits, 3 LSBs are 0.
11 selects NCO B, sine output, 17 bits, 3 LSBs are 0.
12 selects NCO AI, rounded output, 15 bits, 5 LSBs are 0.
13 selects NCO AQ, rounded output, 15 bits, 5 LSBs are 0.
14 selects NCO BI, rounded output, 15 bits, 5 LSBs are 0.
15 selects NCO BQ, rounded output, 15 bits, 5 LSBs are 0.
16-31 selects AGC CIC filter output. 9 MSBs from ch A, next 9 bits from ch B, 2 LSBs are 0.
DITH_A
1b
R/W
1
31
6
0=Disable NCO dither source for channel A. 1=Enable.
DITH_B
1b
R/W
1
31
7
0=Disable NCO dither source for channel B. 1=Enable.
AGC_TABLE
32B
R/W
0
128-159
7:0
RAM space that defines key AGC loop parameters. Format is 32 separate 8-bit, 2’s comple-
ment numbers. This is common to both channels.
F1_COEFF
22B
R/W
0
160-181
7:0
Coefficients for F1. Format is 11 separate 16-bit, 2’s complement numbers, each one spread
across 2 registers. The LSBs are in the lower registers. For example, coefficient h0[7:0] is in
address 160, h0[15:8] is in address 161, h1[7:0] is in address 162, h1[15:8] is in address
163.
F2_COEFF
64B
R/W
0
182-245
7:0
Coefficients for F2. Format is 32 separate 16-bit, 2’s complement numbers, each one spread
across 2 registers. The LSBs are in the lower registers. For example, coefficient h0[7:0] is in
address 182, h0[15:8] is in address 183, h1[7:0] is in address 184, h1[15:8] is in address
185.
a. These are the default values set by a master reset (
MR
). Sync in (
SI
) will not affect any of these values.
Register Name
Width
Type
Default
a
Addr
Bit
Description
Table 5
CLC5902 Control Registers