HackLab.TO Timing Reference A

This is the main timing reference for HackLab.TO (and tick.hacklab.to).

Project Overview

• Built into an American Data 800-series chassis (3U, 10 modules each with line voltage on an edge connector + space for a connector to the back panel)
• Chassis came with 10 AD805 distribution amplifiers (1 BNC in, 1 daisychain out, 6 amplified outputs)
  • Will replace as many as required with other timing-related modules, remaining ones will be used to distribute timing references around

GPS Module

• Will take up 3 slots
• Motorola OnCore UT timing receiver
• 7-segment LED displays for:
  • UTC Time (6 digits, red)
  • Status code (1 digit, red)
  • 4x Tracked SV PRN displays (2 digits each, green)
• LEDs
  • Power (green)
  • Comms (white)
  • 1 PPS (white)
  • OK (blue)
  • Wait (yellow)
  • Fault (red)

GPS Module Status

• 2014-06-16: Bug in the bit writing function, fixed and now can control displays as expected. Also fixed bugs in self-addressing, so that both display driver chips can now be addressed individually. Board hangs randomly after I2C NAKs, need to figure out why this is happening.
• 2014-06-14: Now get a few random segments lit up (wasn't initializing display properly, intensity defaults to zero and scan limit defaults to one), still trying to figure out why I can't get proper digits displayed.
• 2014-06-13: Assembled DISP board and started bringing it up, no lights yet.
• 2014-05-13: DISP board finished and sent to OSH Park for manufacturing.
• 2014-03-06: Tested w/ new antenna connected right to the GPS module, works fine. Likely a board issue with the pass-through, which we can just not use. Next step is to finish the DISP board.
• 2013-11: Received and assembled, GPS communication works but GPS never locks. Need to troubleshoot this further, could be a setup issue, bad GPS board, or an issue with the RF pass-through.
• 2013-10-14: Main board sent to OSH Park for prototype. Display board will be done later.
• 2013-05-16: Main board checklisted, ready for CAM. Display board schematicized, routed. Needs to have mechanical design done and be checklisted.
• 2013-05-15: Main board completely laid out, just needs checklist run.
• 2013-05-13: Chassis is here now and has no PSU, just line voltage going to the cards. Redesigned the module to have a main board (which has the AC/DC converter and most logic on it) and a display board (which has the LED driver and displays on it, and goes on the front panel). Main board is schematicized and 50% laid out now.
• 2013-Early: Designed the module to go on the back of the front panel.

GPS Module Rev 001 Issues

• DISP board centre two bar graphs have LEDs backwards