I had only considered JTAG. The BCM2835 has two “universal” SPI controllers that can shift out 1 to 32 bits at a time. I went back to the Peripheral spec to verify. One thing I hadn’t noticed the first time, was that the Universal SPI controllers were on pins not all brought out to the GPIO header. Argh… I’ll look at one of my Pi to see if the balls are even via-escaped…
Berk On May 2, 2014, at 5:25 AM, [email protected] wrote: >> 3) The BCM2835 SPI controller appears to be flexible enough to use as >> a JTAG master. The current SPI driver couldn’t accommodate JTAG. >> If I go about writing a new driver on the Pi, how should the interface >> look to the application (OOCD specifically). Do you have other JTAG >> interface that you feel is such a good fit, I could use as an example? >> (Or your dream JTAG interface…) > > I do not not much about the hardware limits of the SPI controller inside the > Pi but: > > My first thought is that it probably would be nice to be able to transfer any > numbers of bit, and not be bound to it being dividable by 8. > > For SWD, TX and RX can probably be bound together, but the TX needs to be > able to tri-state unless a an external buffer is used. > > Stian Skjelstad ------------------------------------------------------------------------------ "Accelerate Dev Cycles with Automated Cross-Browser Testing - For FREE Instantly run your Selenium tests across 300+ browser/OS combos. Get unparalleled scalability from the best Selenium testing platform available. Simple to use. Nothing to install. Get started now for free." http://p.sf.net/sfu/SauceLabs _______________________________________________ OpenOCD-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/openocd-devel
