ADS8671 Datasheet, PDF (41/72 Pages) Texas Instruments – 14-Bit, High-Speed, Single-Supply, SAR ADC Data Acquisition System with Programmable, Bipolar Input Ranges

www.ti.com
ADS8671, ADS8675
SBAS779 – DECEMBER 2016
Programming (continued)
7.5.2 Input Command Word and Register Write Operation
Any data write operation to the device is always synchronous to the external clock provided on the SCLK pin.
The device allows either one byte or two bytes (equivalent to half a word) to be read or written during any device
programming operation. Table 5 lists the input commands supported by the device. The input commands
associated with reading or writing two bytes in a single operation are suffixed as HWORD.
For any HWORD command, the LSB of the 9-bit address is always ignored and considered as 0b. For example,
regardless whether address 04h or 05h is entered for any particular HWORD command, the device always
exercises the command on address 04h.
OPCODE
B[31:0]
00000000_000000000_
00000000_00000000
11000_xx_<9-bit address>_
<16-bit data>
11001_xx_<9-bit address>_
00000000_00000000
01001_xx_<9-bit address>_
00000000_00000000
11010_00_<9-bit address>_
<16-bit data>
11010_01_<9-bit address>_
<16-bit data>
11010_10_<9-bit address>_
<16-bit data>
11011_xx_<9-bit address>_
<16-bit data>
All other input command
combinations
Table 5. List of Input Commands
COMMAND
ACRONYM
COMMAND DESCRIPTION
NOP
No operation
•
•
CLEAR_HWORD
•
•
•
READ_HWORD ^•
•
•
READ
•
•
•
•
•
WRITE
•
•
•
•
•
•
SET_HWORD
•
•
Command used to clear any (or a group of) bits of a register.
Any bit marked 1 in the data field results in that particular bit of the specified register being
reset to 0, leaving the other bits unchanged.
Half-word command (that is, the command functions on 16 bits at a time).
LSB of the 9-bit address is always ignored and considered as 0b.
Command used to perform a 16-bit read operation.
Half-word command (that is, the device outputs 16 bits of register data at a time).
LSB of the 9-bit address is always ignored and considered as 0b.
Upon receiving this command, the device sends out 16 bits of the register in the next frame.
Same as the READ_HWORD except that only eight bits of the register (byte read) are
returned in the next frame.
Half-word write command (two bytes of input data are written into the specified address).
LSB of the 9-bit address is always ignored and considered as 0b.
Half-word write command.
LSB of the 9-bit address is always ignored and considered as 0b.
With this command, only the MS byte of the 16-bit data word is written at the specified
register address. The LS byte is ignored.
Half-word write command.
LSB of the 9-bit address is always ignored and considered as 0b.
With this command, only the LS byte of the 16-bit data word is written at the specified register
address. The MS byte is ignored.
Command used to set any (or a group of) bits of a register.
Any bit marked 1 in the data field results in that particular bit of the specified register being set
to 1, leaving the other bits unchanged.
Half-word command (that is, the command functions on 16 bits at a time).
LSB of the 9-bit address is always ignored and considered as 0b.
NOP
No operation
All input commands (including the CLEAR_HWORD, WRITE, and SET_HWORD commands listed in Table 5)
used to configure the internal registers must be 32 bits long. If any of these commands are provided in a
particular data frame F, that command gets executed at the rising edge of the CONVST/CS signal.
Copyright © 2016, Texas Instruments Incorporated
Product Folder Links: ADS8671 ADS8675
Submit Documentation Feedback
41