From 2755c571ffbe3bae7d0485e86b826b9c28e1cbf0 Mon Sep 17 00:00:00 2001 From: Brendan Le Foll Date: Fri, 27 Feb 2015 16:50:55 +0000 Subject: [PATCH] edison.md: add some SPI limitations Signed-off-by: Brendan Le Foll --- docs/edison.md | 3 +++ 1 file changed, 3 insertions(+) diff --git a/docs/edison.md b/docs/edison.md index e4cc6d0..7199373 100644 --- a/docs/edison.md +++ b/docs/edison.md @@ -20,6 +20,9 @@ in libmraa: - i2c is exposed on i2c-6, therfore you must use bus 6 and not bus 0 - PWM avaible on default swizzler postions. (3,5,6,9) - SPI exposed is also used for the ADC. Try not to use your own CS. +- Max SPI speed is 25Mhz/4 ~6.25Mhz +- SPI PM can sometimes do weird things you can disable it with: + echo on > /sys/devices/pci0000\:00/0000\:00\:07.1/power/control - ADC kernel module will return 12bit number but the ADC itself only has an accuracy of 10bits. This ADC is only included on the arduino board. - AIO pins are treated as 0-5 in mraa_aio_init() but as 14-19 for everything -- 2.7.4