Hi all, I am trying to develop a system in which I can communicate with 30+ SPI slaves. The slaves are BMP280 pressure sensors. I currently have a working system with 16 SPI slaves, in which I use SIPO shift registers to control the slave select lines of each sensor (reducing the I/O requirements of the master). One key feature is that I would like to send a 'command' from the master to all the slaves synchronously. To do this I 'disable' the shift register outputs, using the 'enable' pin, and have a pull-down resistor on each of the slave select lines, ensuring they go to Ground.
This system works in practice, however, in my mind seems quite clunky and not particularly scalable ( i.e. for 64 sensors would need 64 resistors....) So I was just wondering if anyone had any advice/suggestions on a different way to produce this system to reduce the amount of hardware required, whilst still keeping the same functionality??