User shall follow flow chart Figure 7-16 to do read from device and Figure 7-17 to do write to device activities.
Note: MCU shall check SPI_RDY pin at least every t8 (max
service interval). t8 = 1ms at SCLK = 6MHz /890μs at SCLK = 4MHz /550μs at SCLK
= 2MHz assuming host starts to read TX FIFO right after detecting SPI_RDY = '1
and SPI bus has 30% idle time in the process of reading 128 bytes.
- For response frame, nCS has to be toggled high after reading the last byte of data in the current buffer.
- tWAIT_READ_MAX
- stack read/single device read from stack devices, with n stack devices, request
m bytes in total (payload + overheads, from all stack devices), wait
time: (n-1)*3μs*2 + m*10μs + 100μs.
- single device read from BQ79600-Q1, request m bytes , wait time:
100μs + m*10μs.
Notes:
- Since write command frame doesn’t incur response frames, host shall discard data from MISO pin.
- If host sends partial data, the device would keep waiting the rest of command data till communication time out happens. Refer to Section 7.3.2.4 for details.