CCS/TMS320C6748: Questions About GPIO Speeds and Boot Modes

Joseph P,

The GPIO peripherals are not considered to be high-speed peripherals. There are other interfaces on the device that are much more high-speed, but if you need the functionality of GPIO then the GPIO is the best option. The speed is dictated by the DSP clock rate, and my expectation is that it will take on the order of 20 DSP clock cycles to read a GPIO register to get one or more bit values. Interestingly, peripheral writes also take about 20 clock cycles, but a small number of write operations will get stored in a write buffer and the DSP code will not require all of those 20 cycles before it moves on to the next instruction. There is a lot more to learn about all of that if you are interested, from the datasheet and User Guides and Reference Guides that you can find on the Product Folder page for the TMS320C6748.

I do not understand your question about storing data in memory. If you have a function GPIO-Read() that returns a value, you store it to memory the same way you would store getchar() or (x + y), by assigning it to a data variable. I have a feeling that your question is beyond what I will be able to help you with.

Boot modes for the device are described in the datasheet and App Notes and especially the TRM. For information on the specifics of your board you can refer to the Technical Reference Manual that comes with the board. One could argue that the boot mode is irrelevant to the application. Tell us what your opinion is from reading through the list of available modes.

Regards,
RandyP