FDC2112-Q1_16 Datasheet, PDF (14/60 Pages) Texas Instruments – Multi-Channel 12-Bit or 28-Bit Capacitance-to-Digital Converter

FDC2112-Q1, FDC2114-Q1, FDC2212-Q1, FDC2214-Q1
SNOSCZ9 – MAY 2016
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MODE
Single channel
Multi-channel
Table 3. Single- and Multi-Channel Configuration Registers
REGISTER
CONFIG, addr 0x1A
MUX_CONFIG addr 0x1B
MUX_CONFIG addr 0x1B
MUX_CONFIG addr 0x1B
FIELD [ BIT(S) ]
ACTIVE_CHAN [15:14]
AUTOSCAN_EN [15]
AUTOSCAN_EN [15]
RR_SEQUENCE [14:13]
VALUE
00 = chan 0
01 = chan 1
10 = chan 2
11 = chan 3
0 = continuous conversion on a
single channel (default)
1 = continuous conversion on
multiple channels
00 = Ch0, Ch 1
01 = Ch0, Ch 1, Ch 2
10 = Ch0, CH1, Ch2, Ch3
The digitized sensor measurement for each channel (DATAx) represents the ratio of the sensor frequency to the
reference frequency.
The data output (DATAx) of the FDC2112 and FDC2114 is expressed as the 12 MSBs of a 16-bit result:
DATA _x
¦_SENSORx ¹²
¦_REFx
(1)
The data output (DATAx) of the FDC2212 and FDC2214 is expressed as:
DATA _x
¦_SENSORx
¦_REFx
28
(2)
Table 4 lists the registers that contain the fixed point sample values for each channel.
CHANNEL ⁽¹⁾
REGISTER ⁽²⁾
DATA_CH0, addr 0x00
0
DATA_LSB_CH0, addr 0x01
DATA_CH1, addr 0x02
1
DATA_LSB_CH1, addr 0x03
DATA_CH2, addr 0x04
2
DATA_LSB_CH2, addr 0x05
Table 4. Sample Data Registers
FIELD NAME [ BITS(S) ] AND
VALUE (FDC2112, FDC2114)
DATA0 [11:0]:
12 bits of the 16 bit conversion
result.
0x000 = under range
0xfff = over range
Not applicable
DATA1 [11:0]:
12 bits of the 16 bit conversion
result.
0x000 = under range
0xfff = over range
Not applicable
DATA2 [11:0]:
12 bits of the 16 bit conversion
result.
0x000 = under range
0xfff = over range
Not applicable
FIELD NAME [ BITS(S) ] AND VALUE
(FDC2212, FDC2214) ⁽³⁾⁽⁴⁾
DATA0 [27:16]:
12 MSBs of the 28 bit conversion result
DATA0 [15:0]:
16 LSBs of the 28 bit conversion result
DATA1 [27:16]:
12 MSBs of the 28 bit conversion result
DATA1 [15:0]:
16 LSBs of the 28 bit conversion result
DATA2 [27:16]:
12 MSBs of the 28 bit conversion result
DATA2 [15:0]:
16 LSBs of the 28 bit conversion result
(1) Channels 2 and 3 are only available for FDC2114 and FDC2214.
(2) The DATA_CHx.DATAx register must always be read first, followed by the DATA_LSB_ CHx.DATAx register of the same channel to
ensure data coherency.
(3) A DATA value of 0x0000000 = under range for FDC2212/FDC2214.
(4) A DATA value of 0xFFFFFFF = over range for FDC2212/FDC2214.
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