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GPIO sharing between ARM and DSP
Added by Steven Hill over 10 years ago
According to the information in this link:
http://e2e.ti.com/support/embedded/linux/f/354/t/47756.aspx
the linux side and the DSP side have to partition GPIO resources by bank. But the GPIO pins available on the MityDSP-L138F seem to be only on bank 0. Does the Critical Link linux kernel have some means of partitioning the resources (i.e. pins) on Bank 0 between the ARM and the DSP?
Replies (1)
RE: GPIO sharing between ARM and DSP - Added by Michael Williamson over 10 years ago
Hi Steven,
We don't have any partitioning schemes in place, as it is very application specific. In fact, we don't have DSP based interrupt handling of OMAP-L138 GPIO's incorporated into our released DSP libraries because we don't have a clean way to sort this out.
Normally, if folks need a GPIO with interrupt capability on the DSP core, we recommend using an FPGA based GPIO block (if using an FPGA module) or as you have read you need to ensure that the ARM isn't handling interrupts from a GPIO on the same bank. Note: it's OK for the DSP and ARM to share pins in the same bank if all they are doing is reading or setting the state of the pin, as the GPIO registers provide atomic set and clear registers. It's really only a sticking point for interrupt handling.
At the moment, on the development kit, none of the pins on BANK 0 used by the ARM require / enable interrupts (they are all SPI chip select outputs), so I think you are save to enable interrupts on the DSP if that's what you need to do.
Hope this helps.
-Mike
