Description
The 16C550 Twin Serial Module is exactly what the name suggests. It is one or two serial ports based around one or two 16C550 UART chips for single or dual serial ports. An FTDI compatible header connects to serial devices at 115,200 baud. The 16C550 is already supported in RomWBW and will work with the stock 3.4.0 build onwards.
This module is designed to be either a replacement for the now obsolete SIO/2. It can also be used as an addition to existing serial modules on RomWBW machines..
As a single UART, only the left-hand two thirds of the PCB need to be populated. As a dual UART, the additional components on the right-hand side need to be fitted too. A single (Standard Bus) or double (Enhanced Bus) connector will be supplied as appropriate.
In dual UART configuration the second serial port can be configured to run at a different speed to the primary serial port through use of a cuttable link/jumper.
The base address is set by a single jumper per port. If used as the only serial module, then just set it at Port 0x80. For the stock build of RomWBW 3.4.0 use port 0xA0 or 0xA8. RomWBW 3.5.0 onwards can use 0x80, 0x88, 0xA0 or 0xA8. In total, up to 8 serial ports can be supported in RomWBW after editing the config file and building a custom ROM.
Note that the16C550 Twin Serial Module is natively supported on RomWBW based RC2014 kits, such as the RC2014 Zed and RC2014 Zed Pro. There is a version of CP/M for the RC2014 Pro or upgraded Mini, Mini II, Classic or Classic II if you wish to use this module and burn your own ROM. Similarly, a version of MSBASIC for the RC2014 Micro, Mini, Mini II, Classic or Classic II is available.
For the PCB Only option, see the Core Module PBC listing
