Datasheet

ADS1255
ADS1256
SBAS288K − JUNE 2003 − REVISED SEPTEMBER 2013
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36
RREG: Read from Registers
Description: Output the data from up to 11 registers starting with the register address specified as part of the command.
The number of registers read will be one plus the second byte of the command. If the count exceeds the remaining registers,
the addresses will wrap back to the beginning.
1st Command Byte: 0001 rrrr where rrrr is the address of the first register to read.
2nd Command Byte: 0000 nnnn where nnnn is the number of bytes to read – 1. See the Timing Characteristics for the
required delay between the end of the RREG command and the beginning of shifting data on DOUT: t
6
.
DOUT
DIN
0001 0001 0000 0001
1st Command
Byte
2nd Command
Byte
MUX ADCON
Data
Byte
Data
Byte
t
6
Figure 34. RREG Command Example: Read Two Registers Starting from Register 01h (multiplexer)
WREG: Write to Register
Description: Write to the registers starting with the register specified as part of the command. The number of registers that
will be written is one plus the value of the second byte in the command.
1st Command Byte: 0101 rrrr where rrrr is the address to the first register to be written.
2nd Command Byte: 0000 nnnn where nnnn is the number of bytes to be written – 1.
Data Byte(s): data to be written to the registers.
DIN
0101 0011 0000 0001
1st Command
Byte
2nd Command
Byte
DRATE Data IO Data
Data
Byte
Data
Byte
Figure 35. WREG Command Example: Write Two Registers Starting from 03h (DRATE)
SELFCAL: Self Offset and Gain Calibration
Description: Performs a self offset and self gain calibration. The Offset Calibration Register (OFC) and Full-Scale
Calibration Register (FSC) are updated after this operation. DRDY
goes high at the beginning of the calibration. It goes
low after the calibration completes and settled data is ready. Do not send additional commands after issuing this command
until DRDY
goes low indicating that the calibration is complete.
SELFOCAL: Self Offset Calibration
Description: Performs a self offset calibration. The Offset Calibration Register (OFC) is updated after this operation. DRDY
goes high at the beginning of the calibration. It goes low after the calibration completes and settled data is ready. Do not
send additional commands after issuing this command until DRDY
goes low indicating that the calibration is complete.
SELFGCAL: Self Gain Calibration
Description: Performs a self gain calibration. The Full-Scale Calibration Register (FSC) is updated with new values after
this operation. DRDY
goes high at the beginning of the calibration. It goes low after the calibration completes and settled
data is ready. Do not send additional commands after issuing this command until DRDY
goes low indicating that the
calibration is complete.