JAJSCA2B June 2016 – January 2018 ADS8910B , ADS8912B , ADS8914B
PRODUCTION DATA.
As shown in Table 4, the host controller can use any of the four legacy, SPI-compatible protocols (SPI-00-S, SPI-01-S, SPI-10-S, or SPI-11-S) to write data to the device.
PROTOCOL | SCLK POLARITY
(At CS Falling Edge) |
SCLK PHASE
(Capture Edge) |
SDI_CNTL | SDO_CNTL | NO. OF SCLK
(Optimal Command Frame) |
TIMING DIAGRAM |
---|---|---|---|---|---|---|
SPI-00-S | Low | Rising | 00h | 00h | 22 | Figure 50 |
SPI-01-S | Low | Falling | 01h | 00h | 22 | Figure 51 |
SPI-10-S | High | Falling | 02h | 00h | 22 | Figure 52 |
SPI-11-S | High | Rising | 03h | 00h | 22 | Figure 53 |
At power-up or after coming out of any asynchronous reset, the device supports the SPI-00-S protocol for data-read and data-write operations.
To select a different SPI-compatible protocol, program the SDI_MODE[1:0] bits in the SDI_CNTL register. This first write operation must adhere to the SPI-00-S protocol. Any subsequent data transfer frames must adhere to the newly selected protocol.
Figure 50 to Figure 53 detail the four protocols using an optimal command frame; see the Timing Requirements and Switching Characteristics tables for associated timing parameters.
NOTE
As explained in the Data Transfer Frame section, a valid write operation to the device requires a minimum of 22 SCLKs to be provided within a data transfer frame.
Any data write operation to the device must continue to follow the SPI-compatible protocol selected in the SDI_CNTL register, irrespective of the protocol selected for the data-read operation.