Using spidev¶
TODO: Provide more context
Configuring SPI4 on the devkit
Pin function | ARM pin | Devkit connector |
SPI4_SCLK | pinmuxed to N7 | J5-12 on devkit |
SPI4_D1 | pinmuxed to R4 | J5-13 on devkit |
SPI4_D0 | pinmuxed to N9 | J5-10 on devkit |
SPI4_CS0 | pinmuxed to P9 | J5-8 on devkit |
Setup pinmux in u-boot: https://support.criticallink.com/gitweb/?p=processor-sdk-u-boot.git;a=commitdiff;h=658f00171b0033c393b103e9ca39584d826bc213;hp=8888d032bca7c9e6a2331b274ca27848e1347735
Setup mcspi4 in linux: https://support.criticallink.com/gitweb/?p=processor-sdk-linux.git;a=commitdiff;h=7b3880db4969f146482d48db21caa637b551d232
Removed spidev warning...: https://support.criticallink.com/gitweb/?p=processor-sdk-linux.git;a=commitdiff;h=d207d2432202215fab4295d7fbd8e276ab0375a9
Build linux spidev_test:
$ make O="build-mitysom57x" -C tools/spi/ $ scp build-mitysom57x/spidev_test eth:
Connect logic analyzer:
Run spidev_test
root@mitysom-am57x:~# ./spidev_test -D /dev/spidev1.0 -v spi mode: 0x0 bits per word: 8 max speed: 500000 Hz (500 KHz) TX | FF FF FF FF FF FF 40 00 00 00 00 95 FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF F0 0D | ......@......................ð. RX | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | ................................
Spi signals seen on spi4_sclk and spi4_d0
Note: spidev_test is just to send some signal over the spi bus to make sure the pinmux and kernel config is in place
libdaq¶
For an example userpace library, see libdaq dac8554.cpp
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