Datasheet

SCLK
DIN
Command
Byte
Command
Byte
t
(1)
SCLKDLY
ADS1281
SBAS378D –AUGUST 2007–REVISED JUNE 2010 www.ti.com
COMMANDS
The commands listed in Table 21 control the In Read Data Continuous mode, the ADS1281 places
operation of the ADS1281. Command operations are conversion data on the DOUT pin as SCLK is
only possible in Register mode. Most commands are applied. As a consequence of the potential conflict of
stand-alone (that is, 1 byte in length); the register conversion data on DOUT and data placed on DOUT
reads and writes require a second command byte in resulting from a register or Read Data By Command
addition to the actual data bytes. operation, it is necessary to send a STOP Read Data
Continuous command before Register or Data Read
A delay of 24 f
CLK
cycles between commands and
By Command. The STOP Read Data Continuous
between bytes within a command is required, starting
command disables the direct output of conversion
from the last SCLK rising edge of one command to
data on the DOUT pin.
the first SCLK rising edge of the following command.
This delay is shown in Figure 52.
(1) t
SCLKDLY
= 24/f
CLK
(min).
Figure 52. Consecutive Commands
Table 21. Command Descriptions
COMMAND TYPE DESCRIPTION 1st COMMAND BYTE
(1) (2)
2nd COMMAND BYTE
(3)
WAKEUP Control Wake-up from Standby mode 0000 000X (00h or 01h)
STANDBY Control Enter Standby mode 0000 001X (02h or 03h)
SYNC Control Synchronize the A/D conversion 0000 010X (04h or 5h)
RESET Control Reset registers to default values 0000 011X (06h or 07h)
RDATAC Control Read data continuous 0001 0000 (10h)
SDATAC Control Stop read data continuous 0001 0001 (11h)
RDATA Data Read data by command
(4)
0001 0010 (12h)
RREG Register Read nnnnn register(s) at address rrrrr
(4)
001r rrrr (20h + 000r rrrr) 000n nnnn (00h + n nnnn)
WREG Register Write nnnnn register(s) at address rrrrr 010r rrrr (40h + 000r rrrr) 000n nnnn (00h + n nnnn)
OFSCAL Calibration Offset calibration 0110 0000 (60h)
GANCAL Calibration Gain calibration 0110 0001 (61h)
(1) X = don't care.
(2) rrrrr = starting address for register read and write commands.
(3) nnnnn = number of registers to be read/written – 1. For example, to read/write three registers, set nnnnn = 2 (00010).
(4) Required to cancel Read Data Continuous mode before sending a command.
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