Rainbow Electronics MAX1204 - Manual (Page 11)

MAX1204
5V, 8-Channel, Serial, 10-Bit ADC
with 3V Digital Interface
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Table 2. Control-Byte Format
Table 3. Channel Selection in Single-Ended Mode (SGL/
DIF
= 1)
SEL1 SEL0
0 0 0
CH4 CH5 SEL2 CH6 CH7 GND
–
1 0 0 – +
0 0 1 – +
1 0
CH0
+
1 – +
0 1
CH1
0 + –
1 1
CH3
0 + –
0 1
CH2
1 + –
1 1 1 + –
Table 4. Channel Selection in Differential Mode (SGL/
DIF
= 0)
SEL1 SEL0
0 0 0
CH4 CH5 SEL2 CH6 CH7
0 0 1 – +
0 1 0 + –
0 1
CH0
+
1 + –
1 0
CH1
–
0 – +
1 0
CH3
1 + –
1 1
CH2
0 – +
1 1 1 – +
PD0
Bit 0
(LSB)
SGL/ DIF
Bit 2
PD1
Bit 1
UNI/ BIP
Bit 3
SEL 0
Bit 4
Bit 7
(MSB)
SEL 1 SEL 2 START
Bit 5 Bit 6
1 = unipolar, 0 = bipolar. Selects unipolar or bipolar conversion mode. In unipolar mode, an
analog input signal from 0V to V REF can be converted; in bipolar mode, the signal can range
from -V REF / 2 to +V REF / 2.
1 = single ended, 0 = differential. Selects single-ended or differential conversions. In single-
ended mode, input signal voltages are referred to GND. In differential mode, the voltage dif-
ference between two channels is measured. (Tables 3 and 4.)
Selects clock and power-down modes.
PD1
PD0 Mode
0 0 Full power-down (I DD = 2µA, internal reference)
0 1 Fast power-down (I DD = 30µA, internal reference)
1 0 Internal clock mode
1 1 External clock mode
These three bits select which of the eight channels is used for the conversion
(Tables 3 and 4).
The first logic 1 bit after CS goes low defines the beginning of the control byte.
Description Name Bit
UNI/ BIP 3
SGL/ DIF 2
PD1
PD0 1
0 (LSB)
SEL2
SEL1
SEL0 6
5
4
START 7 (MSB)