AM3354: SPI Slave register read

user5899310

Part Number: AM3354

Dear TI Team,

We would like to check slave device,connected to SPI1 interface, registers over a terminal(UART0). First of all, I would like to ask you whether it is possible to do that with devmem2 tool, for example just writing "devmem2 0x481A0000" or not. If not possible, could you please tell me another way to read register of slave device register values over terminal(UART0)?

Regards,

Zafer Çalışkan

over 4 years ago

0 Andreas Dannenberg over 4 years ago

TI__Guru 59996 points

Hi Zafer,

as you have probably encountered we currently don't have SPI slave driver support in the Linux SDK (latest info is here: https://e2e.ti.com/support/processors/f/791/t/788237?CCS-AM3352-AM335x-SPI-Slave-driver-for-Linux) which is probably why you try to do that manually in some way.

However there a slave driver for AM335x that somebody developed as part of a "Google Summer of Code" project that you may be able to leverage, see here:

https://github.com/pmezydlo/SPI_slave_driver_implementation/wiki

https://github.com/pmezydlo/SPI_slave_driver_implementation

In theory you could also use the devmem2 tool to do very basic accesses but you would need to include accesses to (re-)configure the McSPI controller for slave mode, and doing so will probably cause some interference with the driver that is running (which you could disable, causing other issues such as now you would need to figure out how to do basic power/clock initialization of the McSPI on your own). I don't think that's worth pursuing really.

Other than that you could use the Processor SDK RTOS code (http://software-dl.ti.com/processor-sdk-rtos/esd/AM335X/latest/index_FDS.html), there are drivers and examples for UART and SPI etc and it should be possible to create some kind of UART-to-SPI-slave bridge without too much trouble if this is what you need (without Linux).

Regards, Andreas

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AM3354: SPI Slave register read