Communications Controller Module v1

This module will communicate with other modules, including the flight computer through the main I2C bus. The purpose of this module is to interface with the Iridium 9602 Satellite Data Modem, and optionally two external serially .

• Sending telemetry Messages to Sat Modem
• Receiving Uplink messages from Sat modem
  • Pass Uplink Messages on to I2C bus addressed to other modules
• Sending telemetry Messages to HF Radio
• Send commands to cutdown

Google Spreadsheet Comm Ctrlr BOM

Main Onboard Devices:

• Arduino FIO
  • XBee for sensor comms
• Sat modem connector
• I2C storage EEPROM(s)
• Connector for VHF APRS ASCII Serial output
  • PWR5, PWR3.3, PWR12, TX, RX, GND
• Connector for HF ASCII Serial output
  • PWR5, PWR3.3, PWR12, TX, RX, GND
• Main Bus connector
• Power Decoupling
  • One 1000uf Electrolytic 25v Cap, 5 0.1uf 0804 surface mount caps stacked in paralle.

See designguide

See Arduino FIO documentation

• Comm CTRLR Software Pseudocode
• Comm CTRLR Software Requirements

For radio interfacing details see also:

• Satellite Modem Digi m10 Details

The The m10 will toggle a logic line high when it has received a message. This signal should interrupt wake up the communications module MCU if it is in sleep mode. The MCU should then read in the message from the m10 module, and pass it on to the appropriate destination. The address of the destination module will be part of the 5-byte command.

The balloon cutdown module will have a short cutdown timer. This timer will be on the order of 30 minutes or so. The timer will be reset by an I2C message from the comms module every time the comms module receives any message from the satellite modem. That means, in addition to forwarding the uplinked message over the I2C bus, you will need to immediately send a direct “reset the counter” heartbeat I2C message over the bus to the cutdown module.

Message content destined for the sat modem or HF modem will be passed raw from module to module if possible, this will reduce the need to change firmware on the comms module.

Messages to be transmitted are to be transmitted immediately upon receipt by the comms module.

Comms module should be able to respond with a configuration request listing which radios are connected (Sat, HF, VHF). Also should have a status available of all radios, with information such as:

• TX Status (is it transmitting right now)
• How many messages are waiting to be transmitted

Bold indicates REQUIRED connections for flight.

1. IORST
   1. This chooses where to connect the WS GPIO pin from the Flight computer
   2. Options
      1. FIO I/O Pin A7
      2. FIO DTR/Reset pin
2. DTX
   1. SAT Debug Serial Port TX line
   2. Options
      1. DBG
      2. MCU
3. DRX
   1. SAT Debug Serial Port RX line
   2. Options
      1. DBG
      2. MCU
4. TX
   1. SAT HOST Serial Port TX line
   2. Options
      1. HOST
      2. MCU
5. RX
   1. SAT HOST Serial Port RX line
   2. Options
      1. HOST
      2. MCU