Datasheet

MAX1020/MAX1022/MAX1057/MAX1058
10-Bit, Multichannel ADCs/DACs with FIFO,
Temperature Sensing, and GPIO Ports
26 ______________________________________________________________________________________
Table 5c. Clock Mode 11
REFSEL1 REFSEL0
VOLTAGE
REFERENCE
OVERRIDE
CONDITIONS
AUTOSHUTDOWN
REF2
CONFIGURATION
AIN
Inter nal r efer ence tur ns off after scan i s com p l ete. If
i nter nal r efer ence i s tur ned off, ther e i s a p r og r am m ed
d el ay of 218 exter nal conver si on cl ock cycl es.
00
Internal (DAC
and ADC)
Temperature
Inter nal r efer ence r eq ui r ed . Ther e i s a p r og r am m ed
d el ay of 244 exter nal conver si on cl ock cycl es for the
i nter nal r efer ence. Tem p er atur e- sensor outp ut ap p ear s
at D OU T after 188 fur ther exter nal cl ock cycl es.
AIN14/AIN10/AIN6
AIN Internal reference not used.
01
External single-
ended (REF1
for DAC and
REF2 for ADC)
Tem p er atur e
Inter nal r efer ence r eq ui r ed . Ther e i s a p r og r am m ed
d el ay of 244 exter nal conver si on cl ock cycl es for the
i nter nal r efer ence. Tem p er atur e- sensor outp ut ap p ear s
at D OU T after 188 fur ther exter nal cl ock cycl es.
REF2
AIN
Default reference mode. Internal reference turns off
after scan is complete. If internal reference is turned
off, there is a programmed delay of 218 external
conversion clock cycles.
10
Internal (ADC)
and external
REF1 (DAC)
Temperature
Inter nal r efer ence r eq ui r ed . Ther e i s a p r og r am m ed
d el ay of 244 exter nal conver si on cl ock cycl es for the
i nter nal r efer ence. Tem p er atur e- sensor outp ut ap p ear s
at D OU T after 188 fur ther exter nal cl ock cycl es.
AIN14/AIN10/AIN6
AIN Internal reference not used.
11
External
differential
(ADC), external
REF1 (DAC)
Temperature
Inter nal r efer ence r eq ui r ed . Ther e i s a p r og r am m ed
d el ay of 244 exter nal conver si on cl ock cycl es for the
i nter nal r efer ence. Tem p er atur e- sensor outp ut ap p ear s
at D OU T after 188 fur ther exter nal cl ock cycl es.
REF2
Table 5d. Differential Select Modes
DIFFSEL1 DIFFSEL0 FUNCTION
0 0 No data follows the command setup byte. Unipolar-mode and bipolar-mode registers remain unchanged.
0 1 No data follows the command setup byte. Unipolar-mode and bipolar-mode registers remain unchanged.
1 0 1 byte of data follows the command setup byte and is written to the unipolar-mode register.
1 1 1 byte of data follows the command setup byte and is written to the bipolar-mode register.
If any of the above conditions exist, the ADC reference
is always on, but there is a 188 clock-cycle delay
before temperature-sensor measurements begin, if
requested.
Unipolar/Bipolar Registers
The final 2 bits (LSBs) of the setup register control the
unipolar-/bipolar-mode address registers. Set
DIFFSEL[1:0] = 10 to write to the unipolar-mode regis-
ter. Set bits DIFFSEL[1:0] = 11 to write to the bipolar-
mode register. In both cases, the setup command byte