Search found 14 matches
- Wed Mar 03, 2021 4:23 pm
- Forum: Raspberry Pi microcontroller boards
- Topic: DDS Sine Generator, Inline Assembler, 2nd Core, Double PWM Output
- Replies: 4
- Views: 3617
Re: DDS Sine Generator, Inline Assembler, 2nd Core, Double PWM Output
@rgcoldeman, thank you very much to point me to you project, which shows how to use DMA! What I don't understand: How do you know, that these channels are not used by anything? ( I had no knowledge of mem32[], so easy.) Yes, I think, DMA should be able to be clocked at a certain clock rate too and ...
- Wed Mar 03, 2021 8:09 am
- Forum: Raspberry Pi microcontroller boards
- Topic: DDS Sine Generator, Inline Assembler, 2nd Core, Double PWM Output
- Replies: 4
- Views: 3617
Re: DDS Sine Generator, Inline Assembler, 2nd Core, Double PWM Output
Nice work! I've done a DDS generator with a completely different approach, it may be some of the techniques can be combined; it is documented on https://www.instructables.com/Arbitrary-Wave-Generator-With-the-Raspberry-Pi-Pic/ (also a thread here: https://forum.micropython.org/viewtopic.php?f=21&t=9...
- Thu Feb 18, 2021 11:49 am
- Forum: Raspberry Pi microcontroller boards
- Topic: DMA, adresses
- Replies: 24
- Views: 24212
- Mon Feb 08, 2021 9:10 am
- Forum: Raspberry Pi microcontroller boards
- Topic: DMA, adresses
- Replies: 24
- Views: 24212
Re: DMA, adresses
Indeed mem32 is slow. I used viper to get the address of the array to pass on to the registers, not for speed, since it's only for configuration. In another test I compared blink speed between mem32 and ptr (both viper). ptr could get me up to 15.625MHz, (4 clock cycles per loop), mem32 well below 1...
- Mon Feb 08, 2021 8:04 am
- Forum: Raspberry Pi microcontroller boards
- Topic: DMA, adresses
- Replies: 24
- Views: 24212
Re: DMA, adresses
Thanks, it looks very neat!
I've posted a more detailed description of the project on https://www.instructables.com/Arbitrary ... ry-Pi-Pic/
I've posted a more detailed description of the project on https://www.instructables.com/Arbitrary ... ry-Pi-Pic/
- Sun Feb 07, 2021 10:58 pm
- Forum: Raspberry Pi microcontroller boards
- Topic: DMA, adresses
- Replies: 24
- Views: 24212
Re: DMA, adresses
Ah, you refer to the DMA classes posted by mw66 on this list? It looks awesome and I hope those classes or similar will eventually be included with the RP2 micropython. (actually I don't find the implemation of 'SetChannelData' method used in the examples) The code I posted directly writes the DMA r...
- Sun Feb 07, 2021 9:19 pm
- Forum: Raspberry Pi microcontroller boards
- Topic: DMA, adresses
- Replies: 24
- Views: 24212
Re: DMA, adresses
The code is complete. It should work out of the box. I used the original 1.13 RP2 micropython version. Where would you expect a 'SetChannelData' method/function?
- Sun Feb 07, 2021 6:04 pm
- Forum: Raspberry Pi microcontroller boards
- Topic: DMA, adresses
- Replies: 24
- Views: 24212
Re: DMA, adresses
OK it works, it is amazing: true 125Msps AWG without even overclocking, and without CPU!! Trick was to use a second DMA channel to reconfigure with a single write to the READ register the first. The DMA sends 32-bit words but the PIO only consumes 8 bits a time, so there is no delay in the reconfigu...
- Sat Feb 06, 2021 8:19 am
- Forum: Raspberry Pi microcontroller boards
- Topic: DMA, adresses
- Replies: 24
- Views: 24212
Re: DMA, adresses
Just not easy for a newbie trying to stick to micropython... FWIW, you can control the PIO from MicroPython. See https://github.com/micropython/micropython/blob/master/examples/rp2/pio_ws2812.py for an example that uses data from memory to control a pin. Thanks! yes it's very powerful. Anyway the p...
- Fri Feb 05, 2021 7:34 am
- Forum: Raspberry Pi microcontroller boards
- Topic: DMA, adresses
- Replies: 24
- Views: 24212
Re: DMA, adresses
Yes, from what I read in the datasheet it should be possible to do DMA->PIO->GPIO. That's probably the best solution, it gives some extra flexibility on frequency from the PIO clock divider and on the choice of pins. Just not easy for a newbie trying to stick to micropython...