From eb328612b24bbd10b8d8ed10544f7ef238e2866f Mon Sep 17 00:00:00 2001 From: Peter Marheine Date: Mon, 25 Feb 2019 14:56:02 +1100 Subject: [PATCH] Document the requirement for hardware SPI I spent a while fighting with my hardware before working this out- if SPI is disabled in the kernel reads will return all 1s which is very confusing and looks more like something is wired up wrong when it's actually correct. --- README.md | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/README.md b/README.md index 2746d16..3692113 100755 --- a/README.md +++ b/README.md @@ -16,7 +16,10 @@ The EVT boards can be attached directly to the Raspberry Pi as a "hat". When bu The only pins that are required are 5V, GND, CRESET, SPI_MOSI, SPI_MISO, SPI_CLK, and SPI_CS. -You can improve performance by attaching SPI_IO2 and SPI_IO3 and running `fomu-flash` in quad/qpi mode by specifying `-t 4` or `-t q`. +The Pi's hardware SPI interface must be enabled in the kernel- use +`raspi-config` or add `dtparam=spi=on` to `/boot/config.txt` and reboot before +using. You can improve performance by attaching SPI_IO2 and SPI_IO3 and running +`fomu-flash` in quad/qpi mode by specifying `-t 4` or `-t q`. You can get serial interaction by connecting the UART pins, but they are not necessary for flashing. @@ -55,4 +58,4 @@ You can verify the SPI flash was programmed with the `-v` command: ## Checking SPI Flash was Written -You can "peek" at 256 bytes of SPI with `-p [offset]`. This can be used to quickly verify that something was written. \ No newline at end of file +You can "peek" at 256 bytes of SPI with `-p [offset]`. This can be used to quickly verify that something was written.