For the past couple of monts GNSS-disciplined time machines were trying out a lot of my hobby time

For the past couple of monts GNSS-disciplined time machines were trying out a lot of my hobby time

Written by John Miller

Building and distribuiting the TimeHat went well, plus it gave me some added investment to search into several things that i may not have had the opportunity to normally, like obtaining some «real» GNSS timing modules! The machine I became the majority of into was the Nokia FYGM, a GNSS timing receiver made to deal with Nokia cell webpages gear. The FYGM keeps a u-blox LEA-M8T, one of the better timing-focused u-blox modules readily available. Many individuals pick these (along with other) timing segments from decomissioned cell internet through Chinese scrappers and recyclers merely to harvest the radio, but i needed to make sure they’re as «with each other» as is possible.

Unlike common enthusiast GNSS segments, the FYGM features a little extra components onto it, namely an 8051 MCU. You will find more information on this about wiki, right here, so I’ll bare this short. To start out, why-not simply emancipate the M8T out of this panel? We have some reasons:

  • I do not desire to build an innovative new service when it comes to M8T
  • The first panel features top quality electricity materials for M8T and active antenna
  • Additionally supplies exceptional antenna safeguards circuitry
  • The provided aluminium instance is really nice
  • The position LEDs (driven from the MCU) are useful
  • The moment the board shoes, you can obtain the MCU out of our very own means

That MCU, the 8051, started as being sugar daddy sites canada the biggest thorn during my side. Before I had one of these simple devices during my fingers all I’d commit from was ebay listing photos and multiple articles on the TimeNuts subscriber list, but which was enough to get started. Along with antenna input, the FYGM have another connector – a 12 pin DIN amphenol-looking thing. Luckily all the FYGMs i’ve found on the market inclide a completed cable tv to mate with this (using an HDMI connector regarding variety unit end, with CAT7 since the cable by itself), otherwise this connector could be an actual serious pain to handle, becuase it isn’t really an amphenol, or whatever appears to be typically readily available. Best 8 associated with pins about connector are widely-used, Ground, DC in (using any where from 12 to 35v), right after which three RS422 differential sets for Tx, Rx, and PPS. Two RS422 transceivers toward the base on the module supply this signaling. My preliminary purpose was to try and make use of these as-is, and so I got some equipment to work well with RS422 – much more about that later on.

TimeHat a?¤ Nokia FYGM

When i obtained an FYGM within my palms, I begun tracing most of the fittings and headers. I became upset to learn that the RS422 transeivers’ input doesn’t arrive straight from the M8T, but alternatively they through the 8051. This designed which wouldn’t feel spitting aside UART signals straight from M8T, a thing that turned into genuine. Throughout the vibrant side, the four pin connector next to the M8T is, actually, UART straight from the M8T, and thus bypassing the 8051 seemed like a chance, plus it commercially continues to be. The ten pin connector next ot the 8051 was a programming and debugging header for that unit, so probably eventually I’m able to see the configuration out and/or reprogram it making it most useful to me personally. The greater number of quick use that header features could be the open reset pin – losing a jumper between they and ground trigger the 8051 to not start whatsoever, so through UART pins adjacent to the M8T I am able to program with it directly, and completely disregard the MCU. I did not finish doing this however.