Register bit description – Rainbow Electronics ADC12041 User Manual
Page 21
Register Bit Description
CONFIGURATION REGISTER (Write Only)
This is an 8-bit write-only register that is used to program the functionality of the ADC12041 All data written to the ADC12041
will always go to this register only The contents of this register cannot be read
MSB
LSB
b
7
b
6
b
5
b
4
b
3
b
2
b
1
b
0
COMMAND
SYNC
BW
SE
ACQ TIME
FIELD
Power on State
10 Hex
b
1
– b
0
The ACQ TIME bits select one of four possible acquistion times in the SYNC-OUT mode (b
4
e
0) (Refer to Selectable
Acquisition Time
section page 22)
b
1
b
0
Clocks
0
0
9
0
1
15
1
0
47
1
1
79
b
2
When the Single-Ended bit (SE bit) is set conversion results will be limited to positive values only and any negative
conversion results will appear as a code of zero in the Data register The SE bit is cleared at power-up
b
3
This is the Bus Width (BW) bit When this bit is cleared the ADC12041 is configured to interface with an 8-bit data bus data
pins D
7
– D
0
are active and pins D
12
– D
9
are in TRI-STATE When the BW bit is set the ADC12041 is configured to interface with
a 16-bit data bus and data pins D
12
– D
0
are all active The BW bit is cleared at power-up
b
4
The SYNC bit When the SYNC bit is set the SYNC pin is programmed as an input and the converter is in synchronous
mode In this mode a rising edge on the SYNC pin causes the ADC to hold the input signal and begin a conversion When b
8
is
cleared the SYNC pin is programmed as an 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
7
– b
5
The command field These bits select the mode of operation of the ADC12041 Power-up value is 000 (See Note 22)
b
7
b
6
b
5
Command
0
0
0
Standby command This puts the ADC in a low power consumption mode
0
0
1
Ful-Cal command This will cause the ADC to perform a self-calibrating cycle that will correct linearity and zero
errors
0
1
0
Auto-zero command This will cause the ADC to perform an auto-zero cycle that corrects offset errors
0
1
1
Reset command This puts the ADC in an idle mode
1
0
0
Start command This will put the converter in a start mode preparing it to perform a conversion If in asynchronous
mode (b
4
e
‘‘0’’) conversions will immediately begin after the programmed acquisition time has ended In
synchronous mode (b
4
e
‘‘1’’) conversions will begin after a rising edge appears on the SYNC pin
DATA REGISTER (Read Only)
This is a 13-bit read only register that holds the 12-bit a sign conversion result in two’s complement form All reads performed
from the ADC12041 will place the contents of this register on the data bus When reading the data register in 8-bit mode the
sign bit is extended
MSB
LSB
b
12
b
11
b
10
b
9
b
8
b
7
b
6
b
5
b
4
b
3
b
2
b
1
b
0
sign
Conversion Data
Power on State
0000Hex
b
11
– b
0
b
11
is the most significant bit and b
0
is the least significant bit of the conversion result
b
12
This bit contains the sign of the conversion result 0 for positive results and 1 for negative
21