Search found 154 matches

by ddrown
Wed Feb 21, 2018 2:17 am
Forum: Projects
Topic: LSE RTC calibration
Replies: 15
Views: 263

Re: LSE RTC calibration

Interesting project! I have some data you might find interesting. I collected the temperature vs frequency graph for a single 32KHz crystal on a STM32F031: https://dan.drown.org/stm32/temp-lse.png The temperature was measured by the built-in CPU sensor, and does a decent job (probably because they a...
by ddrown
Sat Feb 03, 2018 4:49 pm
Forum: General discussion
Topic: Proposal. Use forum logins on the wiki
Replies: 12
Views: 277

Re: Proposal. Use forum logins on the wiki

This makes sense to me. The amount of edit activity on the wiki has gone down since the new account form was disabled.
by ddrown
Sat Jan 20, 2018 3:31 am
Forum: Projects
Topic: Time interval counter (13ns resolution)
Replies: 8
Views: 342

Re: Time interval counter (13ns resolution)

Short PDF doc on "jitter" that may be of interest to readers unfamiliar with the subject... https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.sitime.com/api/gated/AN10007-Jitter-and-measurement.pdf&ved=0ahUKEwjA3N-AvuXYAhUDXawKHfPrDxMQFggmMAE&usg=AOvVaw1MIXIeLi3RSYMjCRhLRPIn Thank yo...
by ddrown
Fri Jan 19, 2018 11:59 pm
Forum: Projects
Topic: Time interval counter (13ns resolution)
Replies: 8
Views: 342

Re: Time interval counter (13ns resolution)

The GPS antenna arrived in the mail and I reran my tests, this time it (the offset between the two GPS modules) was much better:

Image

I'll have to experiment with various changes (antenna swap, channel swap, etc) to see the impact to the offsets.
by ddrown
Wed Jan 17, 2018 7:22 pm
Forum: Projects
Topic: Time interval counter (13ns resolution)
Replies: 8
Views: 342

Re: Time interval counter (13ns resolution)

The GPSes 1Hz tick is not precise short term, but long term. Based on module and conditions short term jitter could be XXns- Xuseconds. Thus the tick itself cannot be used as the base for a counter for example. You have to discipline a quality OCXO with the 1Hz tick to get precise output. Yup, the ...
by ddrown
Wed Jan 17, 2018 1:26 am
Forum: Projects
Topic: Time interval counter (13ns resolution)
Replies: 8
Views: 342

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...
by ddrown
Wed Jan 17, 2018 12:32 am
Forum: Projects
Topic: Time interval counter (13ns resolution)
Replies: 8
Views: 342

Time interval counter (13ns resolution)

I wanted to compare two GPS modules, specifically the amount of time between the pulse per second of each of them. I used a STM32F103 as my hardware, and setup two channels on TIM3 as input capture. The timer is running at 72MHz so it has a 13ns resolution. I also setup TIM2 as a slave to count TIM3...
by ddrown
Mon Jan 01, 2018 7:22 pm
Forum: General discussion
Topic: Happy New Year for 2018
Replies: 16
Views: 421

Re: Happy New Year for 2018

Happy New Year!
by ddrown
Fri Dec 15, 2017 11:03 pm
Forum: General discussion
Topic: usb host contr stm32
Replies: 14
Views: 361

Re: usb host contr stm32

Just to make sure I understand what you are asking for:

1. STM32F4x USB serial device, connected to a host that is sending the data
2. The STM32F4x writes that serial data to a USB pen drive on the STM32F4x's second USB bus

Does that cover it?
by ddrown
Sat Dec 09, 2017 10:57 pm
Forum: General discussion
Topic: Password storage on a BluePill
Replies: 35
Views: 760

Re: Password storage on a BluePill

I put together a stm32duino example of the wordlist: https://github.com/ddrown/wordlist Full example with display uses 33KB of flash, so that's not much room for encryption or other things. I can probably cut a bunch of un-needed stuff out of the graphics libraries though. I was thinking maybe it wo...