Search found 136 matches

by ddrown
Mon Oct 09, 2017 10:45 pm
Forum: Code snipplets
Topic: 32-bit timers
Replies: 9
Views: 259

Re: 32-bit timers

dannyf wrote:
Mon Oct 09, 2017 9:02 pm
more than one way of doing the same thing, :)
That's very true!
by ddrown
Mon Oct 09, 2017 8:41 pm
Forum: New users MUST post here first, and let us know a bit about you and your projects
Topic: Greetings From Dallas
Replies: 5
Views: 161

Re: Greetings From Dallas

I'm also in Austin, TX

Welcome!
by ddrown
Mon Oct 09, 2017 8:36 pm
Forum: Code snipplets
Topic: 32-bit timers
Replies: 9
Views: 259

Re: 32-bit timers

I also have a slightly different way of doing this (using the HAL): uint32_t get_counters() { uint16_t tim2_before, tim1, tim2_after; tim2_before = __HAL_TIM_GET_COUNTER(&htim2); tim1 = __HAL_TIM_GET_COUNTER(&htim1); tim2_after = __HAL_TIM_GET_COUNTER(&htim2); if(tim2_before != tim2_after) { if(tim1...
by ddrown
Mon Aug 28, 2017 10:03 pm
Forum: USB bootloader
Topic: Changing PLL settings for 24Mhz XTAL
Replies: 24
Views: 541

Re: Changing the XTAL frequency

I'm trying to use the STM32DUINO bootloader on a custom board, but I cant get the bootloader to run. The micro is an F103R8T7, it has the LED on PC13 and a pull up resistor on PA12 for the USB reset. I have spotted that my board has a 24MHz crystal and I assume the bootloader will not be configured...
by ddrown
Mon Aug 21, 2017 7:46 pm
Forum: Code snipplets
Topic: libmaple version of MCO output
Replies: 6
Views: 275

Re: libmaple version of MCO output

I don't know if it's the same thing, but stevestrongs OV7670 code generates a high frequency clock output, to drive the camera. His OV7670 code uses a timer to generate 18MHz PWM. MCO can be useful for verifying that your clocks are working: HSE, LSE, etc Some of the STM32 chips have a timer input ...
by ddrown
Sun Aug 13, 2017 7:01 pm
Forum: Hardware
Topic: A look inside the DS3231 RTC
Replies: 9
Views: 429

Re: A look inside the DS3231 RTC

Unless you measure 1y long you cannot get precise results (aging, temperature). I got 4secs in 6months with DS3231 (temp 19-28degC, stock reg period) - that is great as well. To go into more detail about your point about aging, this is a few months of data from two TCXOs (not the DS3231, but it sho...
by ddrown
Sun Aug 13, 2017 12:04 am
Forum: Hardware
Topic: A look inside the DS3231 RTC
Replies: 9
Views: 429

Re: A look inside the DS3231 RTC

Also the GPS 1pps outputs are not precise (especially with cheapo modules), the jitter could be huge short time. You need a quality OCXO disciplined by the 1pps output with a large time constant in the loop, like several hours or more, to get a good precision out of it.. The GPS signal can jitter 3...
by ddrown
Sat Aug 12, 2017 6:44 pm
Forum: Hardware
Topic: A look inside the DS3231 RTC
Replies: 9
Views: 429

Re: A look inside the DS3231 RTC

Unless you measure 1y long you cannot get precise results (aging, temperature). I got 4secs in 6months with DS3231 (temp 19-28degC, stock reg period) - that is great as well. That is true, aging is probably around +/-1ppm/year. And my results were under a much narrower temperature range than the ch...
by ddrown
Sat Aug 12, 2017 1:51 pm
Forum: Hardware
Topic: A look inside the DS3231 RTC
Replies: 9
Views: 429

Re: A look inside the DS3231 RTC

I spotted that. I have some of those modules on my raspis. Its actually quite an interesting device, and with a bit of tweaking is pretty accurate. I wonder how accurate you could make it with a bit of oven control and a GPS reference to tune it. No oven control, but I did get around 1 second per y...
by ddrown
Sun Jul 16, 2017 4:57 pm
Forum: IDE's
Topic: STM32CubeMX generates gcc makefiles now
Replies: 10
Views: 454

Re: STM32CubeMX generates gcc makefiles now

I used this with my latest project. It got the name of the USB middleware filenames wrong, but otherwise worked.