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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 NTP client (Archmax): Part 4 [https://blog.dan.drown.org/embedded-ntp-client-ntp-interleaved-mode-part-4/], Part 3 [https://blog.

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 externally. The PTP peripheral has the option to output a PPS that I can compare

STM32MP1 NTP server, part 3

Previous posts: part 1 [https://blog.dan.drown.org/stm32mp1-ntp-server/], part 2 [https://blog.dan.drown.org/stm32mp1-ntp-server-part-2/], NTP client [https://blog.dan.drown.org/embedded-ntp-client-ntp-interleaved-mode-part-3/] The NTP client confirmed that there was a 943ns difference between my two NTP servers. Now, to investigate where it is coming from. Changes

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 the difference between my other two NTP servers with hardware timestamps. Goal 1: synchronize the local clock

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 client enabled by default :(The distro I'm using uses connman by default to manage the

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 it's using hardware timestamps (H) not kernel timestamps (K): it's using

Wifi NTP server

I saw a thread about someone who wanted a low power NTP stratum 1 server that could run off of batteries and could be put somewhere without an internet connection. That had me wondering how an esp8266 would do in that situation. The hardware I put together was an esp8266

glibc/Linux DNS Round Robin

A friend was trying to figure out what glibc is doing with DNS round robin, and information about it is somewhat scarce. He was expecting it to randomly chose an address out of the multiple at the hostname, but it was preferring only one of the addresses. This behavior doesn&

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 events without interrupt latency and jitter. I am hoping that it will both be better than the

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" board because they're cheap and easy to work with. First I put together a simple design