Final Assembly

CDH Board Assembly

Most of the CDH FM board is preassembled by MicroArt. The additional assembly steps that were needed from our end included:

  • Soldering the data and power lines to the CDH board

  • Conformally coating the CDH board on both sides.

The pictures below show the CDH board being conformally coated after which the harnessing cables were soldered.

CDH Watchdog Issue That Prevents From Coding The Board By Causing Reboot

Note: the CDH watchdog had to be disconnected from the microcontroller before in-application programming (IAP) was completed so that we could program the board. Otherwise, if the watchdog is connected, it will cause the CDH board to restart every time we tried to program the board. On the EM this was not an issue because we had jumper pins that we had to connect to in order to connect the watchdog to the microcontroller.

Picture below shows that we cut the watchdog trace to the microcontroller to disconnect it. At the end (once IAP is completed), we will put some solder and complete the connection.

Due to time crunch, we soldered a cable to each end of the cut watchdog trace. Before integration or until in-application programming is completed, the wires are not connected so that the watchdog is disconnected from the microcontroller. Afterwards, we will solder the two cables so that watchdog is connected. This allowed us to:

  • Assemble the boards into the shell

  • While still being able to program the CDH board

  • While still being able to do other tests and software developments

See the pictures below - they show two cables soldered to the cut watchdog trace. See COMMS final assembly page for how we routed this cables so that we can connect them even after satellite is fully assembled.

All other CDH/COMMS module assembly steps are detailed in the COMMS Final Assembly page.