- Board size should comply with PC/104 Standard
- Mounting holes at all 4 corners (see standard for what this should look like)
- PC/104 connector to mate with other subsytem boards
- HARD constraint on board size to be 90mm by 90mm
- Height should not exceed 12mm
- An operating temperature between -40°C and 85°C should be assumed and every component constituting the OBC should be able to operate within this range
- Temperature Sensor
- An onboard temperature sensor must be available to keep track of temperature changes onboard the OBC
- Buck Converter
- Step down 3.3V to 1.2V
- Should be able to provide up to 1A of current
- Ensure a separate power port for 3V3 (header pins so we can use a power supply
- Power protection
- Decide whether we’re using an eFuse or just adding our own reverse polarity protection
- Real Time Clock (RTC)
- Ideally should use SRAM, i.e. non-volatile memory such that loss of power does not cause a full flush of RTC parameters
- Alarms
- microSD Card
- The microSD needs its own SPI port. There are issues with having it share a port with FRAM
- microSD cards don’t seem very reliable. For future competitions, NAND flash or eMMC would probably be better. or SD card
- FRAM
- CAN Transceiver
- Oscillator
- JTAG Header
- QUADRUPLE CHECK that we have the right JTAG header with the right pinouts that will work correctly with out J-Link
- Reset Button
- Confirm whether we are just using the “power-on reset” button or breaking out the “warm reset” button too
- External Watchdog Monitor
- Umbillical Cord
- What will this look like?
- PC 104 Pinout @Kiran Surendran confirm this with other teams Electrical Bus Architecture
- Comms: SPI + I2C
- EPS: CAN, getting 3V3
- Payload : I2C+SPI x 2, I2C
- ADCS: UART, PWM x 3, SPI x 6, PWM x 4
General Notes
- MUST verify all footprints and pinouts manually (learned from when eFuse footprint was created incorrectly)
- Order a stencil with this board
- Check 0805 capacitor footprint, seems small