JAJSFT4C August 2018 – June 2019 ADS9224R , ADS9234R
PRODUCTION DATA.
In this data transfer protocol, the data rate for data transfer can be increased to double data rate. With double data rate, the device launches data on both edges (rising and falling) of the SCLK. The device supports both polarities of the clock and only one phase of clock (CPHA = 1). The read time required for reading the output data word reduces with increases in bus width and data rate. The SDOs that are not enabled by the BUS_WIDTH register are set to tri-state. Table 5 provides the details of different SPI protocols with bus width options and double data rate to read data from the device.
PROTOCOL(1) | SCLK POLARITY (CPOL)(2) | SCLK PHASE(2) | MSB LAUNCH EDGE | BUS WIDTH(5) | tREAD(3)(4) | TIMING DIAGRAM |
---|---|---|---|---|---|---|
SPI-01-S-DDR | Low (CPOL = 0) | Falling (CPHA = 1) | 1st SCLK rising | 1 | [9 × tCLK + k] | Figure 53 |
SPI-11-S-DDR | High (CPOL = 1) | Rising (CPHA = 1) | 1st SCLK falling | 1 | [9 × tCLK + k] | Figure 53 |
SPI-01-D-DDR | Low (CPOL = 0) | Falling (CPHA = 1) | 1st SCLK rising | 2 | [5 × tCLK + k] | Figure 54 |
SPI-11-D-DDR | High (CPOL = 1) | Rising (CPHA = 1) | 1st SCLK falling | 2 | [5 × tCLK + k] | Figure 54 |
SPI-01-Q-DDR | Low (CPOL = 0) | Falling (CPHA = 1) | 1st SCLK rising | 4 | [3 × tCLK + k] | Figure 55 |
SPI-11-Q-DDR | High (CPOL = 1) | Rising (CPHA = 1) | 1st SCLK falling | 4 | [3 × tCLK + k] | Figure 55 |
Figure 53, Figure 54, and Figure 55 illustrate timing diagrams for the SPI-01-S-DDR and SPI-11-S-DDR, SPI-01-D-DDR and SPI-11-D-DDR, and SPI-01-Q-DDR and SPI-11-Q-DDR protocols, respectively.