Search found 59 matches

by castortiu
Sat Jan 20, 2018 3:50 pm
Forum: General discussion
Topic: [SOLVED] Enable interrupts from inside a timer interrupt
Replies: 29
Views: 477

Re: [SOLVED] Enable interrupts from inside a timer interrupt

"please tell us(me) how those pcb's were made ?" Started with electronics again as a hobby about 5 months ago after 20 years of doing nothing with electronics so I was trying to find a quick method to iterate and create prototypes. 1) The board in the center was made with paper toner transfer and et...
by castortiu
Sat Jan 20, 2018 5:48 am
Forum: General discussion
Topic: [SOLVED] Enable interrupts from inside a timer interrupt
Replies: 29
Views: 477

Re: [SOLVED] Enable interrupts from inside a timer interrupt

By the way I did work with shift registers as well, that's not new to me, in fact my first raw Red Matrix version about 3 months ago was using 74hc595d discrete components and did good progress, I made work the matrix in the image below with an Arduino nano for a 24x32 just red channel a 60Hz, 16 to...
by castortiu
Sat Jan 20, 2018 2:21 am
Forum: General discussion
Topic: [SOLVED] Enable interrupts from inside a timer interrupt
Replies: 29
Views: 477

Re: [SOLVED] Enable interrupts from inside a timer interrupt

"if I were to write a driver for this, I would establish a buffer: it contains information about the display's construction (including current frame index, or brightness) and frames. If you write a slave receiver here (spi or uart), you can turn the controller-less display into a common / universal ...
by castortiu
Fri Jan 19, 2018 6:07 pm
Forum: General discussion
Topic: [SOLVED] Enable interrupts from inside a timer interrupt
Replies: 29
Views: 477

Re: [SOLVED] Enable interrupts from inside a timer interrupt

Yes, most of these matrix are based on shift register. And have different scan lines. Most usual is 1/16. Means it has 4 lines A,B,,C,D to control the row 1-16- & 17-32, so if the address is 0b0001 then data will be sent to row 1 AND 17, however has two data lines per color R1, R2, G1, G2, B1, B2 so...
by castortiu
Fri Jan 19, 2018 6:09 am
Forum: General discussion
Topic: [SOLVED] Enable interrupts from inside a timer interrupt
Replies: 29
Views: 477

Re: [SOLVED] Enable interrupts from inside a timer interrupt

Synchronizing the OE with the latching works like a dream and there is no artifact problem at any brightness level and I can go as low as 300Khz for the PWM without any problem. At this point I can't be happier and don't think I'll make any more changes on the display brightness. Steve wrote, "Well,...
by castortiu
Thu Jan 18, 2018 8:08 am
Forum: General discussion
Topic: [SOLVED] Enable interrupts from inside a timer interrupt
Replies: 29
Views: 477

Re: [SOLVED] Enable interrupts from inside a timer interrupt

On further testing I confirmed what I was afraid, "unsynchronized" PWM on OE brings undesirable artifacts to the display, I bumped the PWM frequency from 400Mhz to 1.2Mhz and is barely noticeable however the artifacts are still there as you can see in the image below with and without PWM. I would be...
by castortiu
Thu Jan 18, 2018 6:54 am
Forum: General discussion
Topic: [SOLVED] Enable interrupts from inside a timer interrupt
Replies: 29
Views: 477

Re: [SOLVED] Enable interrupts from inside a timer interrupt

I uploaded a video to youtube to show how smooth is now the steps in control of the brightness with OE and PWM, the phone I have seems to be really good a low light so in the video can't be appreciated but there is a huge difference between brightness (0) and (15). After playing the video several ti...
by castortiu
Thu Jan 18, 2018 6:34 am
Forum: General discussion
Topic: [SOLVED] Enable interrupts from inside a timer interrupt
Replies: 29
Views: 477

Re: [SOLVED] Enable interrupts from inside a timer interrupt

Handling the OE with PWM works great, as long I keep the PWM above 400Khz it doesn't produce any artifact for lower tones since even bit 0 which is the shortest will have up to 8 pulses and I don't need to synchronize with the latching, the reality in my testing I could go down to 200Khz before I st...
by castortiu
Wed Jan 17, 2018 7:15 pm
Forum: Projects
Topic: RGB Matrix animated clock
Replies: 5
Views: 143

Re: RGB Matrix animated clock

Thank you Steve, I could not have it done without your help on the DMA Slave SPI.
by castortiu
Wed Jan 17, 2018 7:11 pm
Forum: General discussion
Topic: [SOLVED] Enable interrupts from inside a timer interrupt
Replies: 29
Views: 477

Re: [SOLVED] Enable interrupts from inside a timer interrupt

I'm not sure when I talked about 200Khz?, only thing I mentioned was that I want to keep the refresh rate above 200Hz. Still didn't get any hint how to change the PWM frequency. Do you know how? Current approach with two timers works fine, and blue pill only take care of rendering so the current app...