This project intends to develop a simple and (relatively) low-cost Linux-based network-connected (Ethernet or WiFi) serial (RS-232) device, that can act as either a console server, or emulate a serial device such as a modem.
Intended hardware features
- Multiple power sources
- PoE
- USB (also doubles as serial debug port)
- External power
- WiFi connection
- Planning on ESP32-C3 via SPI (and maybe UART as fallback)
- Use esp-hosted to interface with Linux
- Likely won't need any external flash, may design in the option just in case
- Ethernet connection
- At least 10/100, undecided on specifics, SG2002 should already have a PHY, so should just need the port and magnetics (if not integrated, needs to support PoE).
- Linux-capable CPU
- Planning on using SG2002 RISC-V SOC
- Running Linux off of micro-SD card
- Possible option for SPI flash?
- RS-232 via DE-9
- Port pinout is as a DCE, as this is the most likely scenario in which the ring indicator would be useful. NULL-modem cable/adapter can be used to switch to DTE pinout.
- Using MAX3237 transceiver to allow full functionality while in DCE mode
- Headers availble to allow for custom daughter boards for different protocols
- Status LEDs
- Separate serlal RX and TX LEDs
- Possible ring-indicator LED
- Possible "remote access active" LED
- Possibly integrating a security chip like the ATECC
- Possibly hardware watchdog
The following footprints were obtained from Digi-Key:
- Amphenol 10067099-400LF: https://www.digikey.com/en/models/4238740