ADS1118_13 Datasheet, PDF (21/38 Pages) Texas Instruments – Ultra-Small, Low-Power, SPI™-Compatible, 16-Bit Analog-to-Digital Converter and Temperature Sensor with Internal Reference

ADS1118
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SBAS457C – OCTOBER 2010 – REVISED FEBRUARY 2013
REGISTERS
The ADS1118 has two registers that are accessible via the SPI port. The Conversion register contains the result
of the last conversion. The Config register allows the user to change the ADS1118 operating modes and query
the status of the devices.
Conversion Register
The 16-bit Conversion register contains the result of the last conversion in binary twos complement format.
Following power-up, the Conversion register is cleared to '0', and remains '0' until the first conversion is
completed. The register format is shown in Table 5.
BIT
NAME
Table 5. Conversion Register (Read-Only)
15 14 13 12 11 10
9
8
7
6
5
4
3
2
1
0
D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
Config Register
The 16-bit Config register can be used to control the ADS1118 operating mode, input selection, data rate, PGA
settings, and temperature sensor mode. The register format is shown in Table 6.
Table 6. Config Register (Read/Write)
15
14
13
12
11
10
9
8
SS
MUX2
MUX1
MUX0
PGA2
PGA1
PGA0
MODE
7
DR2
6
DR1
5
DR0
4
TS_MODE
3
PULL_UP_EN
2
NOP1
1
NOP2
0
NOT USED
Default = 058Bh.
Bit 15
Bits[14:12]
Bits[11:9]
SS: Single-shot conversion start
This bit is used to start a single conversion. SS can only be written when in power-down state and has no
effect when a conversion is ongoing.
When writing:
0 = No effect
1 = Start a single conversion (when in power-down state)
Always reads back as '0' (default).
MUX[2:0]: Input multiplexer configuration
These bits configure the input multiplexer.
000 = AIN_P is AIN0 and AIN_N is AIN1 (default)
001 = AIN_P is AIN0 and AIN_N is AIN3
010 = AIN_P is AIN1 and AIN_N is AIN3
011 = AIN_P is AIN2 and AIN_N is AIN3
100 = AIN_P is AIN0 and AIN_N is GND
101 = AIN_P is AIN1 and AIN_N is GND
110 = AIN_P is AIN2 and AIN_N is GND
111 = AIN_P is AIN3 and AIN_N is GND
PGA[2:0]: Programmable gain amplifier configuration
These bits configure the programmable gain amplifier.
000 = FS is ±6.144 V⁽¹⁾
001 = FS is ±4.096 V⁽¹⁾
010 = FS is ±2.048 V (default)
011 = FS is ±1.024 V
100 = FS is ±0.512 V
101 = FS is ±0.256 V
110 = FS is ±0.256 V
111 = FS is ±0.256 V
(1) This parameter expresses the full-scale range of the ADC scaling. In no event should more than VDD + 0.3 V be applied to this device.
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