This is an FPGA project which allows RS232 access to an IBM Wheelwriter Typewriter.
Using a terminal running at 9600 baud (9600,n,8,1), the user can directly send characters to the typewriter. They can also cut and paste long documents into the terminal, which will be printed by the typewriter. The FPGA uses XON/XOFF for flow control as well as a 1,000 character deep FIFO so that no characters are lost.
It has been tested on an IBM Wheelwriter 5, however other IBM typewriters such as the Wheelwriter 3 and 6 may also work. The only connection needed to the typewriter is via two pins within the access panel at the top rear of the typewriter.
While any FPGA can be used, this project uses the Lattice XO2 Breakout Board which contains a USB interface that provides power and a RS232 serial port. To use the USB serial port, the user will need to populate the two resistors R14 and R15 which connect the RS232 TX and RX lines between the FPGA and the FTDI USB IC.
Alternatively, a second set of RS232 TX and RX pins are available which can be connected to any 3.3V compatible serial port. This was provided to allow to user to connect any type of serial port, including vintage computers. Just make sure the TTL signalling out of the converter is 3.3V to the FPGA. Both serial connections can be connected at the same time, however only one can be used at a time. In both cases, the baud rate is fixed to 9600 baud only.
