Re: [9fans] Pi updates

FWIW, when I was looking at doing a gpio drive I was thinking of something like the following. Devices: #G/gpio/ctl #G/gpio/$pin/ctl #G/gpio/$pin/data #G/gpio/$pin/event ... bing -a '#G' /dev A pin must be configured before use (and only if neither of its data & event

Re: [9fans] Pi updates

On Fri Jan 1 21:15:03 PST 2016, blstu...@bellsouth.net wrote: > On Fri, 1/1/16, erik quanstrom wrote: > > i'm looking @ the gpio interface, and i wonder what the recommended > > technique for sampling a pin might be from a shell script? > > I haven't really used it in

Re: [9fans] Pi updates

On Wed Dec 30 14:27:27 PST 2015, blstu...@bellsouth.net wrote: > On Wed, 12/30/15, Skip Tavakkolian <9...@9netics.com> wrote: > > > - Enhancements for I2C and SPI > > > > is there an updated devrtc3231.c, or a conventional user space > > fs, that uses the new i2c? > > Yes, there's a devi2c

Re: [9fans] Pi updates

On Fri, 1/1/16, erik quanstrom wrote: > i'm looking @ the gpio interface, and i wonder what the recommended > technique for sampling a pin might be from a shell script? I haven't really used it in shell scripts, but if I were going to do so, I'd probably write up a little

Re: [9fans] Pi updates

Thanks for posting your slides and other work Brian. On Wed, Dec 30, 2015 at 5:22 PM, Brian L. Stuart wrote: > On Wed, 12/30/15, Skip Tavakkolian <9...@9netics.com> wrote: > > > - Enhancements for I2C and SPI > > > > is there an updated devrtc3231.c, or a conventional

Re: [9fans] Pi updates

On Wed, 12/30/15, Skip Tavakkolian <9...@9netics.com> wrote: > > - Enhancements for I2C and SPI > > is there an updated devrtc3231.c, or a conventional user space > fs, that uses the new i2c? Yes, there's a devi2c userland interface ported over from Inferno. That's what's being used to drive the

Re: [9fans] Pi updates

> - Enhancements for I2C and SPI is there an updated devrtc3231.c, or a conventional user space fs, that uses the new i2c?

Re: [9fans] Pi updates

On Mon, 12/28/15, Anthony Sorace wrote: > And yes, I’d be interested in seeing your > slides, although you’ve already given me > enough to keep my busy for a bit. Anthony, I've put the slides up in the directory at: http://cs.drexel.edu/~bls96/plan9/ The class met one night a

Re: [9fans] Pi updates

> Excellent.  I had suspected that statement was too restrictive, but hadn't > seen the errata or gotten around to checking on a scope.  I'll update that > today. New versions posted. spiclock() now rounds the divisor up to the smallest even number that results is a clock rate less than or

Re: [9fans] Pi updates

> but http://raspberrypi.org/documentation/hardware/raspberrypi/spi/README.md > has an erratum suggesting "power of 2" should be "multiple of 2".  I have > been using a default divisor of 250 for a 1MHz clock, and that's the frequency > I see on my oscilloscope. Excellent. I had suspected that

Re: [9fans] Pi updates

Thanks, Brian - that all looks very useful to make the pi more amenable to hardware tinkering. One small suggested amendment: your spiclock() says this - /* * According the Broadcom docs, the divisor has to * be a power of 2. This code rounds up so that the * resulting clock is the highest

[9fans] Pi updates

A few months ago I brought up the question of small platforms suitable for a course on small/embedded computing. If you recall the conversation, with input from the collective wisdom, I decided to use the Pi. At that time several people asked if I could share any results from the course that I'm

Re: [9fans] Pi updates

Wow, that’s amazing timing. I was reading about SPI on the Pi, considering getting one of those TFT displays, closed the window to head to bed, and there’s your message. This is super useful, thanks. And yes, I’d be interested in seeing your slides, although you’ve already given me enough to keep

Re: [9fans] Pi updates

Cool! Thank you. -Skip > A few months ago I brought up the question of small > platforms suitable for a course on small/embedded > computing. If you recall the conversation, with input > from the collective wisdom, I decided to use the Pi. > At that time several people asked if I could share >