Thank you all!! This is for the most part what I sussed out. I'll have to check my 165 chip, because I've had this configured with SP1CSn configured as a manual gpio and would pull high then low before the read. The confusing issues was the uint8_t repeated_tx_data for spi_read_blocking() which made me question what the SPI_TX pin was attempting to do during the read.
I'll go give this another try with SPI_CLK, SPI_RX using spi function and SPI_CS as a general gpio and pulling it high, 2ms delay and then low before the blocking read and see if that makes the 165 happy. Yes, the 589 chip would be ideal, but since this is more investigation that production and I have a couple of 165 chips laying around .... you get the drill.
Ultimately I want to hook this back to the 595 and see if I can get the read from the 165 as close in time (clock cycles) to the write to the 595. Since I can place each on a separate SPI, the lack of tri-state capability in the 165 shouldn't matter since it will be the only chip on SPI1 (595 is on SPI0).
That's the plan. I'll either report back solved and with the favorite permutation of the setup, or report where I've become wrapped around the axle again... Thanks!
I'll go give this another try with SPI_CLK, SPI_RX using spi function and SPI_CS as a general gpio and pulling it high, 2ms delay and then low before the blocking read and see if that makes the 165 happy. Yes, the 589 chip would be ideal, but since this is more investigation that production and I have a couple of 165 chips laying around .... you get the drill.
Ultimately I want to hook this back to the 595 and see if I can get the read from the 165 as close in time (clock cycles) to the write to the 595. Since I can place each on a separate SPI, the lack of tri-state capability in the 165 shouldn't matter since it will be the only chip on SPI1 (595 is on SPI0).
That's the plan. I'll either report back solved and with the favorite permutation of the setup, or report where I've become wrapped around the axle again... Thanks!
Statistics: Posted by drankinatty — Mon Aug 04, 2025 2:21 pm