Dossier No.3: Automatic Peripheral Selector

This client manages a rewards programme that interfaces with a Point of Sale system, modem, rewards card printer and an inventory management system. The rewards card printer houses part of the intelligence of the system but it’s weakness is that it only has one serial port to communicate with all other devices in the shop. To complicate matters, the newer machines have only a USB port and no serial port. What to do?

Electronic Partners presented a solution that allows both versions of the machine to operate with all available peripherals. In addition, we integrated the internet gateway and added a clever boot loader to allow remote monitoring and firmware uploads across the internet.

Feature list:

  • Automatic Peripheral SelectorSelect one of four serial ports
  • Ethernet to serial converter
  • Ethernet TCP/IP boot loader
  • USB to serial converter
  • Display selected peripheral
  • EEPROM setting storage
  • Can be USB powered
  • Handshake on all ports
  • Compact design

The Extra Mile

We helped the client by sourcing components, small run manufacture and the testing of the manufactured products.

Technology used:

Microchip PIC18F67J50 microcontroller with USB device port.
ESD-protected RS-232 serial drivers with handshake control.
Standalone Microchip ENC24J60 Ethernet to SPI bridge.
Software Microchip TCP/IP stack.
All firmware written in C.
Hardware designed in Altium Designer.