41 lines
2.1 KiB
Plaintext
41 lines
2.1 KiB
Plaintext
|
|
MicroCore Labs - Arduino Leonards-based IBM Wheelwriter Printer Option
|
|
---------------------------------------------------------------------------
|
|
|
|
|
|
Description:
|
|
------------
|
|
This is an Arduino Software project which allows RS232 access to an IBM Wheelwriter Typewriter.
|
|
|
|
Using a terminal running at 300 baud (300,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.
|
|
|
|
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.
|
|
|
|
I am using an Arduino Leonardo board which uses the ATmega32u4 microcontroller which contains two UART controllers.
|
|
|
|
This design uses both UARTS. One is connected to the host at 300,N,8,1 and the second connects to the IBM Wheelwriter's IBM_BUS
|
|
interface which runs at 188k, N,9,1. The UART is used in a non-standard 9 databits operation which is not directly supported
|
|
by the Arduino software base. I needed to directly write a few registers to active this mode.
|
|
|
|
The IBM_BUS is bi-directional, so the Arduino's UART Transmitter must be deactivated and set to hi-Z so it will not conflict
|
|
with the drivers contained in the typewriter. To save time I simply added a delay to give the typewriter time to ACK on the IBM_BUS
|
|
rather than sample it for the ACK response. Faster printing action could be achieved if a separate bus transceiver was used
|
|
to switch on and off between the Arduino and the typewriter driving the bus.
|
|
|
|
There is very limited buffering in the Arduino's UART transmitter and reciever and I have also provided very shallow buffering,
|
|
so characters must be sent from the host at the pace typical of typing on the typewriter by hand.
|
|
|
|
|
|
|
|
Pinout
|
|
-------
|
|
- The IBM Wheelwriter pins of interest are: 4=GND and 5=IBM_BUS. Pin#1 is on the left when looking at the typewriter from the front.
|
|
- On the Arduino, only the UART TX pin-1 and GND are needed.
|
|
|
|
|
|
|
|
|
|
|