RS232 RS485 USB Converter Board

Features

• for low traffic and low speed application
• mcu, RS232, RS485/RS422, slave usb all can be interchangeable.
• usb side
  • support platform in linux with usb driver
  • simulated uart programming in application level
• rs232 to rs485 side
  • Tested max. baudrate is 115200(i assume more high baudrate can be accepted, but i have not tested)

Technical

RS232

• RS232 Circuit examples

USB

• Host Computer Setting for usb connection
  • Using Solution from FTDI Chips
  • Linux USB Driver and its usb api, a simulate uart api match to usb api FOR ftdichip
  • References
    • beyondlogic for ftdi
    • sourceforge usb driver for ftdi
• chips
  • ds2232c

RS485

• chips
  • Linear Technology Corp., LTC2859 and LTC2861
  • DS3695

Circuit and PCB

• gEDA Project Files

OR Download here, not always updated

gEDA libraries can be download here or more updated, then modify the gafrc inside converter/

• We have components and PCB, Or some have already soldered, if needed email to us: yan

ToDo

• get a usb chips to uart, which with linux driver
  • MCT P87C52UBAA(http://pfranc.com/usb/usb.mhtml)
  • cypress, PSoC with USB
• linux driver
  • driver in linux : http://ftdi-usb-sio.sourceforge.net/
  • usb in linux guide : http://www.linux-usb.org/USB-guide/book1.html
• get a usb to rs232/485 converter driver
  • driver in windows : http://www.hexin-tech.com.cn/
• re-design all PCB boards dimension following a mechanical box
• merge RS232 board and RS232_dspic_prog board together
  • using 5 pins as TTL level connection, adding one more for RS485 ctrl, and pin layouts as "signal power signal power ..."
• In the market, it has so many these kind of converter and very cheap price(<HK100) and they are including a small mechanical box(electronic does not complex, but mechanial box is complex), which is better than what we do by ourself.