MAX1358B Maxim Integrated Products, MAX1358B Datasheet - Page 37

• Manufacturer Part Number: MAX1358B
• Description: Data-Acquisition System
• Manufacturer: Maxim Integrated Products

D
a
t
a
Register Bit Descriptions
ADC Register (Power-On State: 0000 0000 0000 00XX)
The ADC register configures the ADC and starts
a conversion.
ADCE: ADC power-enable bit. ADCE = 1 powers up
the ADC, and ADCE = 0 powers down the ADC.
STRT: ADC start bit. STRT = 1 resets the registers
inside the ADC filter and initiates a conversion or cali-
bration. The conversion begins immediately after the
16th ADC control bit is clocked by the rising edge of
SCLK. The initial conversion requires four conversion
cycles for valid output data. If CONT = 0 when STRT is
asserted, the ADC stops after a single conversion and
holds the result in the DATA register. If CONT = 1 when
STRT is asserted, the ADC performs continuous conver-
sions at the rate specified by the RATE<2:0> bits until
CONT is deasserted or ADCE is deasserted, powering
down the ADC. The STRT bit is automatically deasserted
after the initial conversion is complete (four conversion
cycles; the ADC status bit ADD in the STATUS register
asserts). The current ADC configurations are not affect-
ed if the ADC register is written with STRT = 0. This
allows the ADC and mux configurations to be updated
simultaneously with the S bit in the MUX register.
BIP: Unipolar/bipolar bit. Set BIP = 0 for unipolar mode
and BIP = 1 for bipolar mode. Unipolar-mode data is
unsigned binary format and bipolar is two’s complement.
See the ADC Transfer Functions section for more details.
POL: Polarity flipper bit. POL = 1 flips the polarity of the
differential signal to the ADC and the input to the signal-
detect comparator (SDC). POL = 0 sets the positive mux
output to the positive ADC and SDC inputs, and the neg-
ative mux output to the negative ADC and SDC inputs.
POL = 1 sets the positive mux output to the negative
ADC and SDC inputs, and the negative mux output to
the positive ADC and SDC inputs.
S
16-Bit, Data-Acquisition System with ADC, DACs,
UPIOs, RTC, Voltage Monitors, and Temp Sensor
h
ADCE
MSB
e
e
t
.
______________________________________________________________________________________
i
RATE<2:0>
n
STRT
BIP
POL
CONT: Continuous conversion bit. CONT = 1 enables
continuous conversions following completion of the first
conversion or calibration(s) initiated by the STRT or S
bit. Set CONT = 0 while asserting the STRT bit, or prior
to asserting the S bit to perform a single conversion or to
prevent conversions following a calibration. Set
CONT = 0 to abort continuous conversions already in
progress. When the ADC is stopped in this way, the last
complete conversion result remains in the DATA register
and the internal ADC state information is lost. Asserting
the CONT bit does not restart the ADC, but results in
continuous conversions once the ADC is restarted with
the STRT or S bit.
ADCREF: ADC reference source bit. Set ADCREF = 0
to select REF as the ADC reference. Set ADCREF = 1
to select AV
AV
voltage, select REF and AGND as the differential inputs
to the ADC, with POL = 0 and while ADCREF = 1.
Table 5. Setting the Gain of the ADC
GAIN<1:0>: ADC gain-setting bits. These two bits
select the gain of the ADC as shown in Table 5.
GAIN SETTING (V/V)
DD
voltage without having to attenuate the supply
MODE<2:0>
1
2
4
8
CONT
DD
as the ADC reference. To measure the
GAIN1
ADCREF
0
0
1
1
GAIN<1:0>
X
GAIN0
LSB
0
1
0
1
X
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