RC 2014
Posted by musovern on May 23rd, 2019 in RC2014, Single Board Computers | 1 comment
RC2014 is a simple 8 bit Z80 based modular computer originally built to run Microsoft BASIC. It is inspired by the home built computers of the late 70s and computer revolution of the early 80s. It is not a clone of anything specific, but there are suggestions of the ZX81, UK101, S100, Superboard II and Apple I in here. It nominally has 8K ROM, 32K RAM, runs at 7.3728MHz and communicates over serial at 115,200 baud.
BASIC
Microsoft BASIC 4.7 comes in 2 variations for the RC2014; 32k or 56k. The 32k BASIC will run on the RC2014 Mini, RC2014 Classic, RC2014 Plus and RC2014 Pro, but 56k BASIC will only run on a RC2014 Pro or an expanded Classic or Plus.
This particular implementation was modified from Nascom 2 BASIC by Grant Searle and has been used here with his kind permission. The hardware specific code from the Nascom implemention has been stripped out to form a more generic BASIC, and a few extra commands have been added in. Details on this can be found on Grant Searles website here; http://searle.hostei.com/grant/z80/SimpleZ80.html#RomBasic
The source code can be found here for the 32k BASIC (“R”) and here for the 56k BASIC (“K”)as used in the RC2014 Mini and RC2014 Classic – both of which use a 68B50 ACIA. The serial routine for the SIO/2 found in the RC2014 Plus and RC2014 Pro has been modified from Grants code and this can be downloaded from the Factory ROM GitHub page, designated as “2” for 32k and “4” for 56k.
The original Nascom 2 BASIC manual can be found here http://www.nascomhomepage.com/pdf/Basic.pdf
When you first boot in to BASIC, you are greeted with
Z80 SBC By Grant Searle
CP/M
The RC2014 Pro runs CP/M as standard, or a CP/M Upgrade Kit can be added to the RC2014 Classic or RC2014 Plus. The variation supplied is CP/M 2.2 and, as with BASIC, this has been modified by Grant Searle and is used with his kind permission.
The CP/M Monitor has been modified to allow it to be used with the Pageable ROM Module and CP/M itself has been modified for either the 68B50 ACIA (“1”) or SIO/2 UART (“6”). Note that the CP/M Monitor runs from ROM as the RC2014 is booted up, and CP/M runs from the compact flash after it has been invoked from the Monitor.
The original files can be found on Grant Searles website http://searle.hostei.com/grant/cpm/index.html#ROMFiles
The RC2014 modifications can be found on GitHub https://github.com/RC2014Z80/RC2014/tree/master/CPM
RomWBW
RomWBW is available for any RC2014 model which has the 512k ROM 512k RAM Module upgrade. It can use the Compact Flash Module for storage, and also supports IDE drives, floppy drives and RTC. RomWBW was written by Wayne Warthen and used on the RC2014 with his kind permission.
RomWBW is a ROM-based implementation of CP/M-80 2.2 and Z-System for all RetroBrew Computers Z80/Z180 hardware platforms including SBC 1/2, Zeta 1/2, N8, Mark IV, and RC2014. Virtually all RetroBrew hardware is supported including floppy, hard disk (IDE, CF Card, SD Card), Video, and keyboard. VT-100 terminal emulation is built-in.
The RomWBW ROM loads and runs the built-in operating systems directlyfrom the ROM and includes a selection of standard/useful applicationsaccessed via a ROM disk drive. A RAM disk drive is also providedto allow temporary file storage.
My Unit is currently running RomWBW v2.91
These are some of smbakers pcb board layouts
http://www.smbaker.com/z80-retrocomputing-17-enhanced-z80-cpu-board-for-rc2014
Z80 CPU board
Floppy disk I/O board
PPIDE for hard drive or CF Card media
Serial I/O board
RAM/EPROM board
USB keyboard and VGA out board
RomWBW up and running
Booting off the CF Card
I enjoy the information on your site.
While much more basic than this rc2014, you may be interested in a 8008 machine with reproduction boards being sold by a fellow in Canada. I built one last year and it is extremely fun. MIL MOD8
This is his website
https://va3ngc.weebly.com/mil-mod-80-computer.html
Regards
Craig