16 bit data bus

[DannyFar]

Hi,

I recently purchased a Teensy 4.1 board and I need to use 16 I/O pins as a data bus. For that I need to read/write two bytes from I/O as fast as possible, e.g PINx/PORTx. Is it possible? If not, what is the best way to form 16 bit data bus using Teensy.

Thanks,
Danny

 

[easone]

Your best bet on T4.1 is probably GPIO1 which has bits 16-31 available on pins 14-23, 26, 27, and 38-41.

You can see the detailed pin assignments here:
https://github.com/KurtE/TeensyDocuments/blob/master/Teensy4.1 Pins.pdf

Note that GPIO access is 32 bit only, so you'll have to format your data into the upper two bytes of the word.

 

[easone]

Check out this thread for more info:
https://forum.pjrc.com/threads/57698-Parallel-IO-is-it-possible

The 32 bit register you want to read/write to is GPIO6_DR.

Note the usage of GPIO6 instead of GPIO1, as explained by Paul here:
https://forum.pjrc.com/threads/57717-port-and-toggle-question-T4?p=216620&viewfull=1#post216620

(GPIO[n] is used for DMA access, while GPIO[n+5] is used for CPU access.)