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stm32

A collection of 23 posts

TCXO

TCXO RTC Raspberry Pi Hat, part 2

The motivation for this project is NTP servers in datacenters - it can be expensive to get a GPS antenna on top of other people's buildings with a wire running down into your

  • Dan Drown
4 min read
ntp

TCXO RTC Raspberry Pi Hat

History I'm bringing my RTC Hats [https://blog.dan.drown.org/tag/stratum2/] back online (source code [https://github.com/ddrown/stm32-input-capture-f031] and hardware design [https://github.com/ddrown/stm32-input-capture-f031/tree/master/hardware]

  • Dan Drown
3 min read
ntp

Embedded NTP client/NTP interleaved mode, part 5

I'll test what happens when I plug my embedded NTP client directly into my NTP servers, bypassing the Ethernet switch.  This ends my long running embedded NTP client series. The systems involved Embedded

  • Dan Drown
3 min read
stm32

Embedded NTP client/NTP interleaved mode, part 4

Part 3 [https://blog.dan.drown.org/embedded-ntp-client-ntp-interleaved-mode-part-3/] ended with an unexplained 3us offset, this post will reduce that. Verifying PTP clock sync I wanted to measure the NTP client's PTP clock sync

  • Dan Drown
4 min read
ntp

Embedded NTP client/NTP interleaved mode, part 3

Previous posts: part 1 [https://blog.dan.drown.org/archmax-ntp-client/], part 2 [https://blog.dan.drown.org/embedded-ntp-client-ntp-interleaved-mode-part-2/] In this post, I wrap up my embedded NTP client and use it to measure

  • Dan Drown
5 min read
stm32mp1

STM32MP1 NTP server, part 2

Previous post: https://blog.dan.drown.org/stm32mp1-ntp-server/ [https://blog.dan.drown.org/stm32mp1-ntp-server/] I figured out my offset problem, which was not a PLL problem like I thought. Connman has a NTP

  • Dan Drown
2 min read
ntp

STM32MP1 NTP server

Previous post: Debian for STM32MP1 [https://blog.dan.drown.org/debian-for-stm32mp1/] NIC Hardware Timestamps First step: enable hardware timestamps in chrony.conf: chrony configuration for hardware timestampsNext, enable chrony's measurements log, and verify

  • Dan Drown
2 min read
stm32

Debian for STM32MP1

I bought a STM32MP1 dev board [https://www.st.com/en/evaluation-tools/stm32mp157a-dk1.html] because it has a gigabit NIC with 1588 PTP timestamps as well as hardware timers that can timestamp PPS

  • Dan Drown
2 min read
arduino

2 button keyboard

I wanted a simple keyboard with play and pause media keys to make it convenient to control my music. To handle the USB, I used a STM32F103 based "blue pill [https://wiki.stm32duino.

  • Dan Drown
2 min read
ntp

Embedded NTP client/NTP interleaved mode, part 2

Hardware transmit timestamps added to NTP client.

  • Dan Drown
2 min read
ntp

Embedded NTP client/NTP interleaved mode

NTP client with hardware timestamps

  • Dan Drown
4 min read
gps

GPS module measurements, part 2

After the previous tests [https://blog.dan.drown.org/gps-module-measurements/], I ordered another GPS antenna to improve the signal conditions. They're just the cheap puck style antennas with SMA connectors ($10 on Amazon)

  • Dan Drown
3 min read
gps

GPS module measurements

Starting point I got a u-blox NEO-6M and I wanted to compare it to my NS-T. Since I don't have a frequency counter, I decided to try creating one myself. The hardware I

  • Dan Drown
4 min read
ntp

PPS over USB

Goal For keeping your system clock on time, you can't beat the Pulse Per Second (PPS) signals available from $10 GPS modules. They typically have better than 100 nanosecond accuracy [https://blog.dan.

  • Dan Drown
4 min read
ntp

TCXO RTC Hats: aging & RTC frequency

I'm focusing on oscillator aging and RTC frequency in this post. See also: initial data [https://blog.dan.drown.org/tcxo-rtc-hats-initial-data/], picture [https://blog.dan.drown.org/tcxo-rtc-hats/], other stratum 2 posts [https:

  • Dan Drown
3 min read
stm32

GNUK: Open Source GPG/SSH hardware key storage

I noticed the GNUK [https://www.fsij.org/category/gnuk.html] project had support for the STM32 Blue Pill [http://wiki.stm32duino.com/index.php?title=Blue_Pill]. I've been looking for an

  • Dan Drown
2 min read
ntp

TCXO RTC Hats: Initial data

The TCXO RTC hats [https://blog.dan.drown.org/tcxo-rtc-hats/] are collecting data. I'm focusing on the RTC part in this post. See also: other stratum 2 posts [https://blog.dan.drown.org/

  • Dan Drown
3 min read
ntp

TCXO RTC Hats

My new stratum 2 NTP server hats arrived from Macrofab today! I have a few hand soldering things to do (32khz crystal and headers), and then I can start calibrating them.

  • Dan Drown
1 min read
time

Temperature compensation, part 2

In the last part [https://blog.dan.drown.org/temperature-compensation/], I measured the TCXO to fit a frequency vs temperature curve. Frequency vs Temperature curve Below are the final curves that I went

  • Dan Drown
4 min read
time

Temperature compensation

Temperature effects are usually the largest source of frequency changes in clocks. So I have three temperature sensors on my test system [https://blog.dan.drown.org/frequency-synchronization-without-phase-in-ntp/]. The sensors are: one built

  • Dan Drown
3 min read
time

Frequency synchronization without phase in NTP

I've been working on my high accuracy RTC project [https://blog.dan.drown.org/stm32f030-devboard-with-tcxo/]. Here's a picture of one of the two systems: Connections The TCXO devboard, BME280, and PCF RTC are

  • Dan Drown
4 min read
rtc

RTC comparison

Real Time Clocks I bought two high accuracy RTC (real time clock) modules and wanted to compare them. RTCs are useful for very low power clocks. They can run for years off of

  • Dan Drown
3 min read
stm32

stm32f030 devboard with TCXO

I'm interested in making a high accuracy real time clock (RTC). To experiment with the hardware I need for that, I created a development board based on the STM32F030F4P6 (which is a 20-TSSOP

  • Dan Drown
4 min read
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