In another thread:
I discuss building a fast data logger. Central to that is using a full 32 bit wide bus to maximize throughput. I though it would be useful to break out what's involved in getting a 32 bit wide bus and share it.
Sixteen bits can be done with the stock Teensy 4.1, but 32 bits requires a custom board. I made up a spreadsheet with all the processor pins and how they are used (or not) on the Teensy. The All IO Pins PNG shows all the processor IO with the ones used by Teensy filled in. Functions in parentheses are (I think) all necessary pins. The Minimum IO PNG shows just these pins. So it looks like the 'B' bus and 'EMC' bus are the best candidates, though each has one pin with a necessary function. I'm hoping one of these can be moved. I looked through the code a bit but am having trouble finding where they are used. The ball layout comes from the one posted on PJRC but has the two port possibilities highlighted in yellow? and orange?. I also removed all non-necessary ports I would not need. I do need a few other ports for write clock, etc. as well as an I2C port. The EMC looks better as the pins are closer to the edge of the chip.
Hope this might be useful. Feel free to point out any mistakes!
.
I discuss building a fast data logger. Central to that is using a full 32 bit wide bus to maximize throughput. I though it would be useful to break out what's involved in getting a 32 bit wide bus and share it.
Sixteen bits can be done with the stock Teensy 4.1, but 32 bits requires a custom board. I made up a spreadsheet with all the processor pins and how they are used (or not) on the Teensy. The All IO Pins PNG shows all the processor IO with the ones used by Teensy filled in. Functions in parentheses are (I think) all necessary pins. The Minimum IO PNG shows just these pins. So it looks like the 'B' bus and 'EMC' bus are the best candidates, though each has one pin with a necessary function. I'm hoping one of these can be moved. I looked through the code a bit but am having trouble finding where they are used. The ball layout comes from the one posted on PJRC but has the two port possibilities highlighted in yellow? and orange?. I also removed all non-necessary ports I would not need. I do need a few other ports for write clock, etc. as well as an I2C port. The EMC looks better as the pins are closer to the edge of the chip.
Hope this might be useful. Feel free to point out any mistakes!
.