Datasheet

ADS1240, 1241
18
SBAS173F
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RDATA–Read Data
Description: Read the most recent conversion result from the
Data Output Register (DOR). This is a 24-bit value.
Operands: None
Bytes: 1
Encoding: 0000 0001
Data Transfer Sequence:
RDATAC–Read Data Continuous
Description: Read Data Continuous mode enables the con-
tinuous output of new data on each
DRDY . This command
eliminates the need to send the Read Data Command on each
DRDY
. This mode may be terminated by either the STOPC
command or the RESET command. Wait at least 10 f
OSC
after
DRDY falls before reading.
Operands: None
Bytes: 1
Encoding: 0000 0011
Data Transfer Sequence:
Command terminated when “uuuu uuuu” equals STOPC or
RESET.
D
IN
0000 0001 • • •
(1)
xxxx xxxx xxxx xxxx xxxx xxxx
D
OUT
NOTE: (1) For wait time, refer to timing specification.
MSB Mid-Byte LSB
D
IN
• • •
0000 0011 • • •
(1)
uuuu uuuu uuuu uuuu uuuu uuuu
D
OUT
MSB Mid-Byte LSB
D
OUT
MSB Mid-Byte LSB
DRDY
DRDY
• • •
NOTE: (1) For wait time, refer to timing specification.
COMMANDS DESCRIPTION OP CODE 2
nd
COMMAND BYTE
RDATA Read Data 0000 0001 (01
H
) —
RDATAC Read Data Continuously 0000 0011 (03
H
) —
STOPC Stop Read Data Continuously 0000 1111 (0F
H
) —
RREG Read from REG “rrrr” 0001 rrrr(1x
H
) xxxx_nnnn (# of regs-1)
WREG Write to REG “rrrr” 0101 rrrr(5x
H
) xxxx_nnnn (# of regs-1)
SELFCAL Offset and Gain Self Cal 1111 0000 (F0
H
) —
SELFOCAL Self Offset Cal 1111 0001 (F1
H
) —
SELFGCAL Self Gain Cal 1111 0010 (F2
H
) —
SYSOCAL Sys Offset Cal 1111 0011 (F3
H
) —
SYSGCAL Sys GainCal 1111 0100 (F4
H
) —
WAKEUP Wakup from SLEEP Mode 1111 1011 (FB
H
) —
DSYNC Sync DRDY 1111 1100 (FC
H
) —
SLEEP Put in SLEEP Mode 1111 1101 (FD
H
) —
RESET Reset to Power-Up Values 1111 1110 (FE
H
) —
NOTE: The received data format is always MSB First; the data out format is set by the BIT ORDER bit in the ACR register.
TABLE IV. Command Summary.
The commands listed in Table IV control the operations of
the ADS1240 and ADS1241. Some of the commands are
stand-alone commands (e.g., RESET) while others require
additional bytes (e.g., WREG requires the count and data
bytes).
Operands:
n = count (0 to 127)
r = register (0 to 15)
x = don’t care
ADS1240 AND ADS1241 CONTROL COMMAND DEFINITIONS