[riot-notifications] [RIOT-OS/RIOT] SPI MISO of SPI0 should be pulled down in FRDM-KW41Z (#11460)
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Sat Apr 27 01:04:29 CEST 2019
My FRDM-KW41Z was reseting when communicating with the on-board FLASH (AT45DB041E) via SPI. I was using this configuration to init:
/* from board.h */
#define FLASH_SPI_DEV FRDM_NOR_SPI_DEV
#define FLASH_SPI_MODE SPI_MODE_0
#define FLASH_SPI_CS FRDM_NOR_SPI_CS
#define FLASH_SPI_CLK FRDM_NOR_SPI_CLK
Reading the datasheet of the AT45DB041E it stated:
> The SO pin will be in a high-impedance state whenever the device is deselected (CS is deasserted).
When I probed the MISO pin, it was floating, and for some reason, the chip did not reset when measuring it with and osciloscope, and it sometimes worked fine if I sticked my finger on the MISO pin.
Crearly a floating pin problem on an input pin... I have had these symptoms back when I used PIC18.
This solved the problem:
I tried changing things in cpu/kinetics/spi.c but it wasnt compiling..
ps: I tried this on 2 different FRDM-KW41Z boards with same results.
ps2: I am using a RIOT branch I dont know if this is solved in HEAD, since I need to use KW41Z wireless transceiver. The last commit of the repo is Dec 17 2018: 09ad33f05f458d93d150c6c34501615e63e39fd9
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