I am trying make an expansion board for the debug header on the 6678 and the 6657 EVMs. I am going to use some of the GPIO signals to perform miscellaneous connections to peripherals (like LEDS, chip resets, FPGA initialization etc). On the 6678, GPIO 0 to 15 was brought out to the connector. On the 6657, the McBSP was brought out to the same pins that GPIO0 to 13 occupied. At first, I thought this was OK, but after reading the McBSP specifications, this core does not have the ability to do GPIO like some of of the older McBSP cores did. Also, I noticed that the SPI mode of the McBSP was removed as well which is something I was considering using.
Is there any way of getting the McBSP pins to perform GPIO? From the McBSP user guide, they talk about pins being multiplexed, but I don't think that is the case. The bits to use the GPIO mode (see the McBSP for the DM642) are reserved. Are they there but not documented?
I have also thought about forcing the pins to inputs or tristate and then redirecting the pins through the FPGA. Another possibility would be to directly wire the pins to the connector, but since the GPIO resistor are on the bottom of the board and the connector is a SMT connector on the top, it will get a little messy.
The final design will be using the GPIO pins since I want software compatibility between the two platforms, so the GPIO path would be preferred.
One other thing to note, I will be using the other GPIOs as their native functions. This includes the timers, UARTs and SPI port, so these would not be options to use.
Any thoughts, ideas, or concerns?
Paul
