adc1204802 National Semiconductor Corporation, adc1204802 Datasheet - Page 23

• Manufacturer Part Number: adc1204802
• Description: 12-bit Plus Sign 216khz 8-channel Sampling Analog-to-digital Converter
• Manufacturer: National Semiconductor Corporation

Register Bit Description
CONFIGURATION REGISTER (Write Only)
This is a 13-bit write-only register that is used to program the
functionality of the ADC12048. All data written to the
ADC12048 will always go to this register only. The contents
Power on State: 0100Hex
b
MUX. They select which input channels of the MUX will
b
quistion times in SYNC-OUT mode. (Refer to Selectable
b
results will be limited to positive values only and any nega-
tive conversion results will appear as a code of zero in the
Data register. The SE bit is cleared at power-up.
b
(BW bit b
(BW bit b
of the Configuration Register in 8-bit mode. When this bit is
set and bit b
will program the upper byte of the Configuration register. The
HB bit will automatically be cleared when data is written to
the upper byte of the Configuration register, allowing the
lower byte to be accessed with the next write. The HB bit is
cleared at power-up.
3
5
6
7
–b
–b
: When the Single-Ended bit (SE bit) is set, conversion
: The High Byte bit (HB) is meaningful only in 8-bit mode
MSB
0
4
: The MUX ADDRESS bits configure the analog input
: The ACQ TIME bits select one of four possible ac-
BW
b
12
12
12
= “0”) and is a don’t care condition in 13-bit mode
= “1”). This bit is used to access the upper byte
12
b
= 0, the next byte written to the ADC12048
11
COMMAND FIELD
b
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
b
3
10
b
9
b
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
2
SYNC
b
TABLE 1. MUX Channel Assignment
8
b
b
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
5
HB
1
b
7
b
0
1
0
1
SE
4
b
23
6
b
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
of this register cannot be read.
connect to the MUXOUT+ and MUXOUT− pins. (Refer to the
MUX section for more details on the MUX.) Power-up value
is 0000.
Acquisition Time section.)
b
is programmed as an input and the converter is in synchro-
nous mode. In this mode a rising edge on the SYNC pin
causes the ADC to hold the input signal and begin a conver-
sion. When b
output and the converter is in an asynchronous mode. In this
mode the signal at the SYNC pin indicates the status of the
converter. The SYNC pin is high when a conversion is taking
place. The SYNC bit is set at power-up.
b
operation of the ADC12048. Power-up value is 000. (See
(Note 22))
8
11
Clocks
: The SYNC bit. When the SYNC bit is set, the SYNC pin
–b
b
ACQ TIME
5
9
: The command field. These bits select the mode of
MUXOUT+
15
47
79
9
CH0
CH1
CH2
CH3
CH4
CH5
CH6
CH7
CH0
CH1
CH2
CH3
CH4
CH5
CH6
CH7
15
b
4
cleared, the SYNC pin is programmed as an
b
3
MUXOUT−
MUX ADDRESS
COM
COM
COM
COM
COM
COM
COM
COM
CH1
CH0
CH3
CH2
CH5
CH4
CH7
CH6
b
2
b
1
LSB
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b
0