Datasheet
SLAS284A – AUGUST 2000 – REVISED DECEMBER 2002
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Control Register 1 (see Table 7)
BIT 11 BIT 10 BIT 9 BIT 8 BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0
0 1 RBACK OFFSET BIN/2s R/W RESERVED RESERVED RESERVED RESERVED SRST RESET
Table 11. Control Register 1 Bit Functions
BITS
RESET
VALUE
NAME FUNCTION
0 0 RESET Reset
Writing a 1 into this bit resets the device and sets the control register 0 and control register 1 to the reset values.
To bring the device out of reset, a 0 has to be written into this bit.
1 0 SRST Writing a 1 into this bit resets the sync generator. When running in multichannel mode, this must be set during the
configuration cycle.
2, 3 0,0 RESERVED Always write 0
4 1 RESERVED Always write 0
5 1 RESERVED Always write 0
6 0 R/W R/W, RD/WR selection
Bit 6 of control register 1 controls the function of the inputs RD and WR. When bit 6 in control register 1 is set to
1, WR becomes a R/W input and RD is disabled. From now on a read is signalled with R/W high and a write with
R/W as a low signal. If bit 6 in control register 1 is set to 0, the input RD becomes a read input and the input WR
becomes a write input.
7 0 BIN/2s Complement select
If bit 7 of control register 1 is set to 0, the output value of the ADC is in twos complement. If bit 7 of
control register 1 is set to 1, the output value of the ADC is in binary format. Refer to Table 2 through Table 5.
8 0 OFFSET Offset cancellation mode
Bit 8 = 0 → normal conversion mode
Bit 8 = 1 → offset calibration mode
If a 1 is written into bit 8 of control register 1, the device internally sets the inputs to zero and does a conver-
sion. The conversion result is stored in an offset register and subtracted from all conversions in order to
reduce the offset error.
9 0 RBACK Debug mode
Bit 9 = 0 → normal conversion mode
Bit 9 = 1 → enable debug mode
When bit 9 of control register 1 is set to 1, debug mode is enabled. In this mode, the contents of control register 0
and control register 1 can be read back. The first read after bit 9 is set to 1 contains the value of control register 0.
The second read after bit 9 is set to 1 contains the value of control register 1. To bring the device back into normal
conversion mode, this bit has to be set back to 0 by writing again to control register 1.