Question on HiFive1 Rev B PWM

HiFive1 Rev B
1

Hi all. It’s a pleasure to start being a part of this community.

I’ve been working on an upcoming blog post for using the Freedom Metal SDK GPIO functions, and while doing so went to the schematics of the HF1RB here https://sifive.cdn.prismic.io/sifive%2Fa4546ced-0922-4d87-9334-e97c1a9fd9a5_hifive1.b01.schematics.pdf looking at where all of the GPIO lines end up. From the schematic it appears that there are only 6 PWM GPIO pins, but the main product page says there are 9 of them, and indeed, when I look at the board I can see the ~ on the 6 pin header (labeled 14-19 on the board with ~17, ~18, and ~19). But that isn’t what the schematic would lead me to believe.

Any thoughts on the discrepancy?

Thanks!
Joe

Update: I went ahead and posted my write-up on the GPIO pins here https://dev.iachieved.it/iachievedit/hifive1-rev-b-gpio-pins/ but am still curious about the discrepancy between the board itself (the ~ squiggles on the header for 17, 18, and 19) and the schematics. If anyone can explain or reconcile that I would be grateful!

2

Welcome to the community joe.

Please see these additional docs on the HiFive1 rev B:

The function of GPIO is multiplexed with other functions such as I2C. This can best be visualized on the last page of the Getting Started Guide mentioned above.

1 Like
3

Thanks @Jim for the additional references, I will certainly dig in!