[email protected] wrote: ↑
Fri Jun 21, 2019 11:38 am
DarkElvenAngel wrote: ↑
Sun Jun 16, 2019 8:16 pm
Hello I see to have found an issue with the SPI bus and how to get any kind of speed from it.
I have tried three libraries
BCM2835 no issues with speed
WiringPi seems to max out at 500kHz
Raw SPI seems to max out at 500kHz
This all came about when trying to get my OLED to run faster I assumed the driver was no good and began to write my own. Now that I have a Raw SPI driver written and working I find it suffers from the same speed issue.
Does anyone know how to get more speed from the Raw SPI driver / WiringPi?
Please note I have gotten slower speeds to work.
wiringPi uses the standard Linux kernel driver. As such, the speed is limited by the hardware - excesses of 48Mb/sec have been achieved.
Your issue is LATENCY, not speed. You need to update the whole device using one single giant write rather that (say) a write per pixel.
This makes sense the software I have only transfers one byte at a time I'm working on a better driver but I have limited time to get into it sadly.
Thanks Gordon I knew that you'd have some light to shine on this. Joan had suggested too that I was hitting some sort of limit.
What about this buffer Gordon I read about how on the WiringPi you can increase it how does one do this with out using the gpio command?
Thanks Gordon and thanks Joan I think I have a good idea of what I must do next.