Raspberry Pi Bare Metal Programming with Rust

Re:Raspberry Pi Bare Metal Programming with Rust by bsder on Saturday January 16, 2016 @06:41PM (#10917421)

> Even in Linux if you access the Pi's GPIO registers directly you can toggle pins in a tight loop at around 1-2mhz.

Careful, this is strongly dependent upon the hardware, not Linux.

I seem to recall that people doing SWD programming can barely get the GPIO's to move faster than a couple of KHz.

I can tell you that, at least on the BeagleBone Black, you have to do some Linux driver voodoo to get better than a couple of KHz.

Edit: I stand corrected. Apparently the Broadcom chip in the RPi does much better than the TI one in the BeagleBone Black when driving baseline GPIO's.

[ Parent | on HN ]

Re:Raspberry Pi Bare Metal Programming with Rust by fpgaminer on Sunday January 17, 2016 @02:11AM (#10918654)

On the other hand, the BBB has two dedicated on-chip MCU's for driving the GPIO's.

[ Parent | on HN ]

Re:Raspberry Pi Bare Metal Programming with Rust by bsder on Sunday January 17, 2016 @02:34AM (#10918702)

True, but those are really annoying to program and are mostly meant for hard real-time rather than maximum speed.

The speed on the BBB for GPIO's is okay (I can get to about 12.5MHz with some care). It's more annoying that you actually have to be in supervisor mode to change the I/O direction of a GPIO pin.

[ Parent | on HN ]