Search found 203 matches

by dannyf
Sat Jan 20, 2018 5:48 pm
Forum: Hardware
Topic: 16 BIT HX8357C
Replies: 7
Views: 30

Re: 16 BIT HX8357C

I wired my screen to bluepill like this
those things generally assume a set of wiring that's consistent with the hardware. so you just need to make sure that your wiring matches the code - or what the code assumes. if not, change the wiring or change the code, until they match.
by dannyf
Sat Jan 20, 2018 2:56 pm
Forum: General discussion
Topic: [SOLVED] Enable interrupts from inside a timer interrupt
Replies: 29
Views: 432

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

20180119_211651.jpg (241.71 KiB)
for large matrix, that's a pin efficient but not time efficient implementation: as the row data is serial as well.

a better approach is to use a mux (or multiples of them).
by dannyf
Sat Jan 20, 2018 2:54 pm
Forum: General discussion
Topic: [SOLVED] Enable interrupts from inside a timer interrupt
Replies: 29
Views: 432

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

o the PWM algorithm needs to be very efficient
that's probably the disconnect. Take a look at hc595's datasheet and see how the OE pin works with respect to the rest of the circuitry.
by dannyf
Fri Jan 19, 2018 7:37 pm
Forum: General discussion
Topic: [SOLVED] Enable interrupts from inside a timer interrupt
Replies: 29
Views: 432

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

looks like yours has a 16:4 mux that controls which line is on, and then 3 sets of shift registers, for R/G/B. 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 ...
by dannyf
Fri Jan 19, 2018 12:30 pm
Forum: General discussion
Topic: [SOLVED] Enable interrupts from inside a timer interrupt
Replies: 29
Views: 432

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

if it has serial inputs, a latch and an OE pin, it is likely that it is based on serial shifters like HC595 where the OE pin is completely unhinged from the input circuitry.

implementing ppm over pwm hardware just makes zero sense.
by dannyf
Thu Jan 18, 2018 11:34 am
Forum: General discussion
Topic: [SOLVED] Enable interrupts from inside a timer interrupt
Replies: 29
Views: 432

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

There is also the option to feed a timer from another timer.
having the master to trigger to slave; or running the slave in single pulse mode....
what means T1C3N next to it???
negative.
by dannyf
Wed Jan 17, 2018 6:48 pm
Forum: General discussion
Topic: [SOLVED] Enable interrupts from inside a timer interrupt
Replies: 29
Views: 432

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

I need to run the PWM at least 1000 times faster. It is certainly possible to run the pwm module at 1Mhz. But when your requirement becomes that extreme for such a simple task, you may want to re-examine your approach, both software and hardware. Case in point. Ppm is often used as a software imple...
by dannyf
Wed Jan 17, 2018 1:50 pm
Forum: Libraries & Hardware
Topic: Stm32f103C8 External Dac
Replies: 21
Views: 353

Re: Stm32f103C8 External Dac

If you want speed, don't use digitalWrite, unroll the loop and use a pointer to index the array.
by dannyf
Wed Jan 17, 2018 11:59 am
Forum: General discussion
Topic: [SOLVED] Enable interrupts from inside a timer interrupt
Replies: 29
Views: 432

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

for indoor applications, duty cycle of 0.1% or lower is indistinguishable from dark, even if high brightness LEDs are involved. that percentage is higher for outdoor applications. so if you are refreshing your display at 100Hz (way higher than necessary), the minimum on cycle you need to hit is 0.1%...
by dannyf
Wed Jan 17, 2018 12:55 am
Forum: Projects
Topic: Time interval counter (13ns resolution)
Replies: 8
Views: 194

Re: Time interval counter (13ns resolution)

so I could use both 16 bit timers together as a pseudo 32 bit timer. if there is something else going on on your chip - like another ISR on UART or ADC, a composite timer may show jitter consistent with the pattern shown in your measurement. Those chips allow chaining / master + slave pair of two t...