
XRD98L63
14
Rev.1.01
Serial Interface Readback
The readback function is used to view the content of
the serial interface registers as well as several key
registers in the ofset calibration logic. Readback is
enabled by writing a 1 to the RBenable bit (D9) of the
Readback register.
In the readback mode, the content of the selected
register is output on the 10 MSBs of the ADC output
bus pins DB[11:2]. As long as valid clocks and CCD
signal are applied, the calibration will continue to
function properly during readback (internally the ADC
data is still sent to the calibration logic).
Registers are selected for readback by writing to the
RBreg[8:0] bits in the Readback register, bits D8 to D0.
If RBreg[8:6]=000, then RBreg[5:0] are used to ad-
dress the serial interface registers. Currently only
register addresses 0 to 23, 62 and 63 are defined. If
RBreg[8:6]
≠000, then RBreg[5:0] are ignored and
RBreg[8:6] are used to address registers in the calibra-
tion logic.
RBenable RBreg[8] RBreg[7] RBreg[6] RBreg[5] RBreg[4] RBreg[3] RBreg[2] RBreg[1] RBreg[0]
Selected Register
Register Number
0
x
none (ADC data output)
1
0
PGA00
0
1
0
1
Offset
1
0
1
0
PGA01
2
1
0
1
PGA10
3
1
0
1
0
PGA11
4
1
0
1
0
1
OB Even Gain
5
1
0
1
0
OB Odd Gain
6
1
0
1
Even Line
7
1
0
1
0
Odd Line
8
1
0
1
0
1
Calibration
9
1
0
1
0
1
0
Wait A
10
1
0
1
0
1
Wait B
11
1
0
1
0
OB Lines
12
1
0
1
0
1
CDAC Even
13
1
0
1
0
CDAC Odd
14
1
0
1
FDAC Even
15
1
0
1
0
FDAC Odd
16
1
0
1
0
1
Control
17
1
0
1
0
1
0
Test
18
1
0
1
0
1
Polarity
19
1
0
1
0
1
0
Clock
20
1
0
1
0
1
0
1
SBLKdly
21
1
0
1
0
1
0
SPIXdly
22
1
0
1
0
1
ADCdly
23
1
0
1
0
ReadBack
62
1
0
1
Reset
63
1
0
1
x
Average Even (internal)
Cal 1
1
0
1
0
x
Average Odd (internal)
Cal 2
1
0
1
x
CDAC Even (internal)
Cal 3
1
0
x
CDAC Odd (internal)
Cal 4
1
0
1
x
FDAC Even (internal)
Cal 5
1
0
x
FDAC Odd (internal)
Cal 6
1
x
Gain (internal)
Cal 7
Table 2. Readback Register Selection