ADS1255IDB Burr-Brown Corporation, ADS1255IDB Datasheet - Page 34

• Manufacturer Part Number: ADS1255IDB
• Description: Very Low Noise/ 24-Bit Analog-to-Digital Converter
• Manufacturer: Burr-Brown Corporation

ADS1255
ADS1256
SBAS288D − JUNE 2003 − REVISED AUGUST 2004
COMMAND DEFINITIONS
The commands summarized in Table 24 control the operation of the ADS1255/6. All of the commands are stand-alone
except for the register reads and writes (RREG, WREG) which require a second command byte plus data. Additional
command and data bytes may be shifted in without delay after the first command byte. The ORDER bit in the STATUS
register sets the order of the bits within the output data. CS must stay low during the entire command sequence.
RDATA: Read Data
Description: Issue this command after DRDY goes low to read a single conversion result. After all 24 bits have been shifted
out on DOUT, DRDY goes high. It is not necessary to read back all 24 bits, but DRDY will then not return high until new
data is being updated. See the Timing Characteristics for the required delay between the end of the RDATA command and
the beginning of shifting data on DOUT: t
34
NOTE: n = number of registers to be read/written − 1. For example, to read/write three registers, set nnnn = 2 (0010).
r = starting register address for read/write commands.
COMMAND
SELFOCAL
SELFGCAL
SYSOCAL
SYSGCAL
STANDBY
SELFCAL
WAKEUP
WAKEUP
RDATAC
SDATAC
RESET
RDATA
WREG
RREG
SYNC
DOUT
DRDY
SCLK
DIN
Completes SYNC and Exits Standby Mode
Completes SYNC and Exits Standby Mode
Synchronize the A/D Conversion
Offset and Gain Self-Calibration
Stop Read Data Continuously
Figure 29. RDATA Command Sequence
Reset to Power-Up Values
System Offset Calibration
Read Data Continuously
System Gain Calibration
0000 0001
Offset Self-Calibration
Gain Self-Calibration
Begin Standby Mode
Read from REG rrr
6
Table 24. Command Definitions
Write to REG rrr
.
DESCRIPTION
Read Data
t
6
MSB
Mid− Byte
1ST COMMAND BYTE
1111 0000
1111 0001
0000 0011
0000 1111
1111 0010
1111 0100
0000 0000
0000 0001
1111 0011
1111 1100
1111 1101
1111 1110
1111 1111
0001 rrrr
0101 rrrr
LSB
(FCh)
(FDh)
(FEh)
(0Fh)
(F0h)
(F1h)
(F2h)
(F3h)
(F4h)
(FFh)
(00h)
(01h)
(03h)
(1xh)
(5xh)
2ND COMMAND BYTE
0000 nnnn
0000 nnnn
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