SBAS774B May 2016 – December 2021 ADC32RF80 , ADC32RF83
PRODUCTION DATA
The ADC has a set of internal registers that can be accessed by the serial interface formed by the SEN (serial interface enable), SCLK (serial interface clock), and SDIN (serial interface data) pins. Serially shifting bits into the device is enabled when SEN is low. SDIN serial data are latched at every SCLK rising edge when SEN is active (low), as shown in Figure 8-56. The interface can function with SCLK frequencies from 20 MHz down to low speeds (of a few hertz) and also with a non-50% SCLK duty cycle, as shown in Table 8-25.
The SPI access uses 24 bits consisting of eight register data bits, 12 register address bits, and four special bits to distinguish between read/write, page and register, and individual channel access, as described in Table 8-26.
MIN | TYP | MAX | UNIT | ||
---|---|---|---|---|---|
fSCLK | SCLK frequency (equal to 1 / tSCLK) | 1 | 20 | MHz | |
tSLOADS | SEN to SCLK setup time | 50 | ns | ||
tSLOADH | SCLK to SEN hold time | 50 | ns | ||
tDSU | SDIN setup time | 10 | ns | ||
tDH | SDIN hold time | 10 | ns | ||
tSDOUT | Delay between SCLK falling edge to SDOUT | 10 | ns |
SPI BIT | DESCRIPTION | OPTIONS |
---|---|---|
R/W bit | Read/write bit | 0 = SPI write 1 = SPI read back |
M bit | SPI bank access | 0 = Analog SPI bank (master) 1 = All digital SPI banks (main digital, interleaving, decimation filter, JESD digital, and so forth) |
P bit | JESD page selection bit | 0 = Page access 1 = Register access |
CH bit | SPI access for a specific channel of the JESD SPI bank | 0 = Channel A 1 = Channel B |
ADDR[11:0] | SPI address bits | — |
DATA[7:0] | SPI data bits | — |
Figure 8-57 shows the SDOUT timing when data are read back from a register. Data are placed on the SDOUT bus at the SCLK falling edge so that the data can be latched at the SCLK rising edge by the external receiver.