THS10064
10-BIT 6 MSPS, SIMULTANEOUS SAMPLING
ANALOG-TO-DIGITAL CONVERTER
SLAS255 – DECEMBER 1999
21
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
analog input channel selection (continued)
control register 1 (see Table 8)
– – BIT 9 BIT 8 BIT 7 BIT 6
– – RESERVED OFFSET BIN/2s R/W
BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0
DATA_P DA TA_T TRIG1 TRIG0 OVFL/FRST RESET
Table 12. 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. In addition the FIFO pointer and of fset register is reset. After reset, it takes 5 clock cycles until the first
value is converted and written into the FIFO.
1 0 OVFL
(read only)
FRST
(write only)
Overflow flag (read only)
Bit 1 of control register 1 indicates an overflow in the FIFO.
Bit 1 = 0 → no overflow occurred.
Bit 1 = 1 → an overflow occurred. This bit is reset to 0, after this control register is read from the processor.
FRST: FIFO reset (write only)
By writing a 1 into this bit, the FIFO is reset.
2, 3 0,0 F0, F1 FIFO trigger level
Bit 2 and bit 3 of control register 1 are used to set the trigger level for the FIFO. If the trigger level is reached,
the signal DAT A_A V (data available) becomes active according to the settings of DATA_T and DA T A_P. This
indicates to the processor that the ADC values can be read. Refer to Table 13.
4 1 DATA_T DATA_AV type
Bit 4 of control register 1 controls whether the DATA_AV signal is a pulse or static (e.g for edge or level
sensitive interrupt inputs). If it is set to 0, the DAT A_AV signal is static. If it is set to 1, the DAT A_A V signal is a
pulse. Refer to Table 14.
5 1 DATA_P DA TA_AV polarity
Bit 5 of control register 1 controls the polarity of DAT A_AV . If it is set to 1, DA TA_A V is active high. If it is set to 0,
DATA_AV is active low. Refer to Table 14.
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 T able 3 through Table 6.
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 conversion. The conversion result is stored in an offset register and subtracted from all conversions in order
to reduce the offset error.
9 0 RESERVED Always write 0.