--- title: "AVR Experiments & Prototypes" url: "https://maker.wiznet.io/WIZnet/resellers/avr-experiments-prototypes/" markdown_url: "https://maker.wiznet.io/WIZnet/resellers/avr-experiments-prototypes/md" type: "VAR: Value-Added Reseller Products" author: "sgitheach" author_url: "http://www.sgitheach.org.uk/exp.html" editor: "WIZnet" editor_url: "https://maker.wiznet.io/" original_author: "sgitheach" original_url: "http://www.sgitheach.org.uk/exp.html" published: "2023-04-26" language: "en" hardware: ["WIZnet W5100"] likes: 0 views: 149 comments: 0 source: "WIZnet Makers (https://maker.wiznet.io/)" --- # AVR Experiments & Prototypes > AVR Experiments & Prototypes Original author: sgitheach (source: http://www.sgitheach.org.uk/exp.html) ## Components - **WIZnet W5100** x 1 ([docs](https://docs.wiznet.io/Product/Chip/Ethernet/W5100)) ## Article **DETAILS** The [rubidium atomic clock](http://www.sgitheach.org.uk/atomic.html) requires an accurate time source to initially set the time. Originally I used a RS232 GPS puck but I then looked for something home grown. The answer was to use sime NTP Client to obtain the time from an internet time server and send the date and time as text to the atomic clock. This simple NTP client uses a w5100 ethernet chip and a mega32 for its intelligence. This site may be personal technical tutorial site about AVR tech. in this site, there are 3 ethernet module for prototype. 2 are W5100 based modules and 1 is ENC28J60 module. in detail, please visit He also wrote useful example for network moudle like “NTP Client”. in detail, visit but we’re afraid, there is no source code. however he opened the hardware schematic. > ## ***Schematic and PCB*** > > *The *[*Eagle*](http://www.cadsoft.de/)* files can be downloaded *[*here*](http://www.sgitheach.org.uk/ntp/eagle.zip)*.* > > *![](http://www.sgitheach.org.uk/ntp/ntp_s.png)![](http://www.sgitheach.org.uk/ntp/ntp_b.png)* --- Source: https://maker.wiznet.io/WIZnet/resellers/avr-experiments-prototypes/