Hi Everyone
I have pretty much done my research but I am not confident that what I am setting out to do is correct, I was hoping to post here and double check my logic.
I want to wire wrap circuits that will have either no firmware or will have a microcontroller set up as a SPI slave.
I can control my parallel port with inb, outb and ioperm or with ioctr. I am still investigating ppdev.
If I toggle the data lines up and down and read the signal on my oscilloscope the square wave "digital-like" signal is not regular. This is expected as I am running a regular Linux distro, Trisquel and I am not expecting real-time performance.
My question, if the PC is the SPI master, is it okay if the SPI bus is synchronous but has an inconsistent frequency?
If I use the strobe line,as the SPI clock, SCLK, both master and slaves will be using the same clock but if the those clock pulses are not equal, I don't know if bad things can happen.
If I had a microcontroller that was set up as a SPI slave, could it obey an on-board clock and also an SPI clock signal coming from the PC that was of a bit of an irregular frequency?
I will also be sending out a byte in parallel that will need to be processed by the SPI devices in a serial manner. If I bit mask out bits from a byte, one-by-one and send each bit at the same position in the parallel byte, will the SPI device respond once it was received 8 bits, assuming it has an 8 bit wide shift register?
If anyone has any general pointers about interfacing SPI and a PC, I would appreciate any time you can spare.
Thanks !
I have pretty much done my research but I am not confident that what I am setting out to do is correct, I was hoping to post here and double check my logic.
I want to wire wrap circuits that will have either no firmware or will have a microcontroller set up as a SPI slave.
I can control my parallel port with inb, outb and ioperm or with ioctr. I am still investigating ppdev.
If I toggle the data lines up and down and read the signal on my oscilloscope the square wave "digital-like" signal is not regular. This is expected as I am running a regular Linux distro, Trisquel and I am not expecting real-time performance.
My question, if the PC is the SPI master, is it okay if the SPI bus is synchronous but has an inconsistent frequency?
If I use the strobe line,as the SPI clock, SCLK, both master and slaves will be using the same clock but if the those clock pulses are not equal, I don't know if bad things can happen.
If I had a microcontroller that was set up as a SPI slave, could it obey an on-board clock and also an SPI clock signal coming from the PC that was of a bit of an irregular frequency?
I will also be sending out a byte in parallel that will need to be processed by the SPI devices in a serial manner. If I bit mask out bits from a byte, one-by-one and send each bit at the same position in the parallel byte, will the SPI device respond once it was received 8 bits, assuming it has an 8 bit wide shift register?
If anyone has any general pointers about interfacing SPI and a PC, I would appreciate any time you can spare.
Thanks !