Ruptor wrote:Pr0f wrote:sadly the QL's serial ports are best considered rudimentary at best. I certainly wouldn't chose to add external keyboard through them.
Could you elaborate?
In my world if an rs232 passes bytes it works and a keyboard would pass bytes across it.
I could try -
serial comms (RS232) is provided by SER1 and SER2 on the QL - one was wired as DTE and the other as DCE, although they only implement DTR / CTS handshaking. The IPC chip handles only the receive side of the serial ports, the ZX8302 chip only the transmit side of the serial ports. The DTR and CTS handshaking for the transmit and receive sides of the interface are handled in the driver software, or the firmware (for receive) but not by hardware - so it's easily possible to overrun a buffer or lose a character. The buffers are not particularly large, so a faster device will easily overwhelm a QL. If anything else is using the ZX8302 - such as Microdrive access or network access - your serial ports won't be doing any output.
In the standard QL - you would be lucky to get 9600 baud running on one port, you certainly would not get 19200. Operating the 2 serial ports at different board rates is not possible on the standard QL.
The PS/2 protocol is a reasonably fast clocked (clk and data lines only) protocol, that would just about be managable to translate to a serial port running at 9600, providing it did not drop characters and could keep up. The AT keyboard interface protocol is similar to the Ps/2 and could be considered a subset, but the connector is different.