Lumir Vanek - RC2014

Introduction - RC2014 Pro

This page describes my experience with RC2014 external link 8-bit computers, based on famous Zilog Z80 processor.

I ordered RC2014 Pro kit on Tindie external link and received bunch of PCB's and components ...

Assembling

... then I spent two afternoons and nights with soldering. Everything is perfectly documented and if you do assembling and soldering closely it works without any troubleshoting.

RC2014 Pro consist from 7 boards:

Main board - it's passive backplane, it contains bus connectors, input jack, power switch and indication LED. It's possible to add 7805 stabilizer for powering from voltage over 5V.
Dual clock board - there is crystal, frequency dividers and jumpers for choosing output frequency. It generates clock for processor and serial board.
Processor board, there is only Z80 CPU and four pull-up resistors.
64 kB RAM board.
Pageable ROM board - it's divided to pages, that contains different content: BASIC, CP/M loader and some pages are void.
Serial board - there is Z80 SIO/2 dual serial port. First channel is obviously used for connection to PC via FTDI converter. Second one is free for custom use.
Compact Flash Storage Module - CP/M for RC2014 is modified to be able use it as emulated Floppy disc. User can use A: - P: drives. A 128MB CF card is split in to 15 x 8MB drives and 1 x 2MB drive.

Boards
Main board	Z80 CPU	64 kB RAM
Pageable ROM	Dual clock	SIO/2 serial port

Aditional modules

Digital I/O board

There is 'must have' module: Digital I/O external link board, that contains 8 buttons and 8 LED's. It's perfect for learning basic I/O operations.

Z80 PIO, Z80 CTC

I have four SC103 external link Z80 PIO modules and one SC102 with Z80 CTC from Small Computer Central.

Z80 PIO, Z80 CTC modules
Z80 PIO and 32 LED's	Two PIO's driving 32 LED's	IEO connecting to bus	Int. daisy-chain with official SIO/2 module

PIO's are connected to LED's using ULN2803A Darlingtons. It's perfect for learning how shift and rotation instructions works external link .

I wrote the program that periodically fires interrupts from Z80 CTC. This program fires two independent interrupt routines - from channels #0 🡺 #1 and #2 🡺 #3. Those routines use RRC external link / RLC / RR / RL instructions to make rotation effects. For correct function is necessary to connect IEO signal (pin #7) on SIO/2 module to bus pin #38 and put jumper on CTC board that connect this line to IEI pin on CTC. This establishes Interrupt Daisy-Chain external link (page #9).

Z80 SIO/2

I moved official SIO/2 module to another computer and built SC104 external link Z80 SIO module.

Channel B is routed to enhanced bus (green and yellow jumpers) and is used by WiFi module. IEO is routed to bus #38 using wire jumper and used by CTC IEI.

WiFi module

Another interesting toy is WiFi module external link . It's connected to channel B of SIO/2 module through enhanced bus. It allows connect to second channel remotely using Telnet session.

WiFi module
Delivery	Building	Final module
ASM source	Java source	Running

This video external link shows controlling two power relays over WiFi using JAVA Telnet client. Here is my program that's testing buttons on I/O board and sends commands to SIO channel B, which is connected to WiFi module. On another PC is running Java telnet client, that's receiving those commands and switching ON/OFF my two power relays in my IOT solution. Also is possible read IOT sensors values and display it back on RC2014 console.

Z80 DMA

I built Z80 DMA module on Prototype PCB external link .

Z80 DMA module

For testing DMA I wrote program that sends programming sequence to Write Registers and starts memory-to-memory transfer.

I have also tested memory-to-I/O transfer by sending ASCII arts from DMA 🡺 SIO/2 🡺 WiFi modules to remote telnet session. Video here external link . For memory-to-I/O transfer, SIO/2 W/!RDYB output #30 must be connected to DMA input RDY #25. I use RC2014 #40 bus line for it.

SC108 – Z80 CPU, ROM and RAM module

When I used up all the BackPlane Pro slots, I decided to buy SC108 external link module. I removed original CPU, ROM and RAM modules and gained two free slots.

ROM on this board contains Small Computer Monitor which is able to load CP/M from standard RC2014 Compact Flash module. Then ROM is paged out and 64kB RAM is used. BTW this module has 128kB RAM, but second 64kB bank not easy to use. Only one software that I know to do it is te editor external link and HiTech C compiler enhancements modified by Ladislau Szilagyi. It requires modified CP/M.

There is 74HCT74 dual flip-flop on this board (on 0x38H). First half is used to page IN/OUT ROM. Second one is used for switching between RAM banks. I have added two LEDs on unused output #8, so I can see which bank is selected.

Running CP/M 2.2

I use PuTTY external link for connecting to CP/M terminal. On images you can see session setting.

PuTTY Terminal
Finished computer	Keyboard setting	Serial setting	CP/M 2.2

MBASIC

On this archive external link is possible to download Microsoft BASIC Interpreter v5.21 for CP/M. To load any COM file is necessary use Binary to CP/M Package. It converts MBASIC.COM file to text and then it's possible to paste it to PuTTY terminal (by mouse Right-click over window) and store file to CP/M disc using download.com command.

Installing and running MBASIC
Installing MBASIC	Running MBASIC

Developing software in assembler

For developing software for RC2014 I use different ways - I've tried four assemblers:

CP/M Assembler reads i8080 assembly-language source files from the disk and produces 8080 machine language in Intel hex format.
TASM is assembler, that is able to compile code for many 8bit processors. It works on Windows environment.
ZAS - HI-TECH SOFTWARE Z80 Macro Assembler that's part of HI-TECH C 3.09. It works on CP/M or Emulator on Windows environment.
Z80 Simulator IDE

Editing ASM, AS and C sources

For editing sources I use Notepad++ external link on PC or ZDE 1.6 editor on CP/M.

Another good editor is te external link .

TASM Development environment

In source directory I have following files:

Tasm.exe + Tasm80.tab - assembler files
FilePackage.exe + msbvm60.dll + Comdlg32.ocx - converter from binary to text
*.asm files - assembler sources
*.bat - scripts for compiling
BIN directory, where compiled binaries are stored
LST directory - listing outputs

Compiling: I run script like this: tasm -t80 -b hello.asm ./BIN/hello.com ./LST/hello.lst. If everything is OK, I can see result and compiled file is in BIN directory:

ZAS Development environment

On RC2014 I have HI-TECH C Compiler 3.09 for CP/M installed on drive I: and *.AS sources on drive H:. So I can run commands like: I:ZAS -L -W120 H:test-asm.as and I:LINK -Z -C100H -Otest-asm.com test-asm.OBJ to build H:test-asm.com and run it.
On PC I have HI-TECH C Compiler 3.09 for CP/M with emulator somewhere. So I can run: cpm_orig ZAS -L -W180 test-asm.as and cpm_orig LINK -Z -Pbss -C100H -Otest-asm.com test-asm.OBJ to build it and then run cpm_orig test-asm. Note that emulator don't support IN / OUT instructions.

Transfering files from PC to RC2014

To store binary files (*.COM created by TASM or ZAS on emulator) to RC2014 using terminal, it needs convert it to text like this:

Open packaged file. You can see, that text contains three parts:

Invoking A:DOWNLOAD.COM program, parameter is filename to store, HELLO.COM in this case
User identity, don't care about it
Hexadecimal code of stored binary file and CRC

I usually modify first line like A:DOWNLOAD.COM X:filename.ext (where X: is a target drive), copy file to clipboard (^A ^C) and then make right mouse click on PuTTY terminal. DOWNLOAD.COM get file content from terminal and stores it to destination disc. It's work like a charm.

Z80 Simulator IDE

Z80 Simulator IDE external link is not directly related to RC2014, but it's useful software to learn Z80 assembler in Windows environment. It contains emulator, assembler, disassembler and debugger for the Zilog Z80 CPU, BASIC compiler and many more features.

Z80 Simulator IDE

HI-TECH C Compiler 3.09 for CP/M

On this page external link is info about C compiler for CP/M.

Building and running AES-256 demo

In subdirectory examples/aes256 there is very interesting demo. I compiled it by following command:

I:c -V H:demo.c H:aes256.c

And here is screenshot that shows torturing Z80 CPU with this demanding computation:

I have installed C compiler on disc I: and sources on H: so building command is e.g.: I:c -V H:hello.c.
If you compile a program which uses floating point arithmetic (i.e. real numbers) you MUST specify to the compiler that the floating point library should be searched. This is done with a –LF option at the END of the command line, e.g.: I:c -V H:quadr-eq.c -LF.
For editing C sources I use ZDE 1.6 editor.
If I need send source file to PC, I run PuTTY on it and connect via telnet to WiFi module (that's connected to SIO/2 module channel B) and use PIP command like this: C:PIP PUN:=H:filename.c. Source appears in PuTTY and it's possible to select it and press ^C to copy it to clipboard.

HI-TECH C Compiler 3.09 with emulator

On this GIT repository external link is HI-TECH-C-V3.09 with CP/M emulator. So it's easy to compile C sources on PC and then run COM's on emulator. As usually I use Windows packager by Grant Searle to move COM's to my RC2014.

Using inline assembler in C sources

I have simple C source that mix assembler code using #asm and #endasm compiler directives.

It can be compiled on PC using emulator like cpm_orig c -V hello.c, but can't be run, because there are OUT instructions - unsuported by emulator.

On native CP/M (like on RC2014) it can be compiled and it runs external link without problems: I:c -V H:hello.c.

DX-Forth (with emulator)

Here external link is DX-Forth 4.45. It's possible run it on RC2014 or on emulator by the same way as HI-TECH C.

Borland Turbo Pascal

On this archive external link is possible download Borland Turbo Pascal 3.01a for CP/M-80. Installation is same as MBASIC, I used FilePackage and modified text file to have pascal in drive P:.

Borland Turbo Modula

On this archive external link is possible download Borland Turbo Modula-2 for CP/M-80. Installation is same as MBASIC, I used FilePackage and modified text file to have modula in drive M:.

Digital Research PL/I Compiler for CP/M-80

On this page is possible download PL/I Compiler external link for CP/M-80. PL/I is a programming language oriented towards scientific and business programming. Digital Research provided implementations for their CP/M operating system as well as MS-DOS.

This PL/I program computes the largest of three numbers:

/**********************************************/
/* This program computes the largest of three */
/* FLOAT BINARY numbers x, y, and z.          */
/**********************************************/

test:
	procedure options(main);
	declare
		(a,b,c) float binary;

	put list ('Type Three Numbers:');
	get list (a,b,c);
	put list ('The Largest Value is',max3(a,b,c));

/* this procedure computes the largest of x, y, and z */
max3: procedure(x,y,z) returns(float binary);

	declare
		(x,y,z,max) float binary;

	if x > y then
		if x > z then
			max = x;
		else
			max = z;
	else
		if y > z then
			max = y;
		else
			max = z;
	return(max);
end max3;

end test;

To build LARG3NUM.PLI use following approach:

Compiling: pli LARG3NUM
Linking: link LARG3NUM
Then run it: LARG3NUM

Building and running PL/I sample

I you are familiar with C language, good start point to learn PL/I is this page external link .

Micro Focus COBOL for CP/M 2.2

On this page is possible download COBOL Compiler external link for CP/M-80.

MicroPro office software

Company MicroPro external link created office package with text editor WordStar , spreadsheet CalcStar and another applications: DataStar, ReportStar, InfoStar, SuperSort etc.

When running with TerraTerm WordStar 4.0 have nice highlighted menu. Unfortunately CalcStar 1.45 not have it.

Games

On this page external link is possible to download games for CP/M. For CatChum (like "Pac-Man") it's necessary to slow down CPU speed to not be eaten in one second.

RTM/Z80 - Retro Tiny Multitasking system for Z80

On this page external link is announced RTM/Z80 - a multitasking kernel, built for Z80. Here I have collected some notes about getting it to work.

Z80-SIM

For build RTM/Z80 is necessary to install Z80-SIM external link .

Preparing Z80-SIM on Linux (Debian 10.4 in my case): Download z80pack-1.37.tgz and extract in your home directory. Follow instructions on chapter "Quickstart to run the Digital Research OS's". I doing this as root. Then:

cd z80pack-1.37/cpmsim/

In cpmsim directory:

ln disks/library/hd-tools.dsk disks/drivei.cpm
cpmls -f z80pack-hd disks/drivei.cpm
mkdskimg i
mkdskimg j
./cpm2

Note: Make cpm2 eXecutable before to try run it. If everything is OK, Z80-SIM is started and you can see CP/M console.

On CP/M shell explore drives:

A>dir
A>dir B
A>dir I
A>dir J

Use A:bye command to exit CP/M emulator.

Cpmtools 2.21

This package allows to access CP/M file systems and transer files between Linux filesystem and CP/M drives.

Download cpmtools-2.21.tar.gz external link . and extract it in your Linux home directory to cpmtools-2.21 and folllow instrunctions in INSTALL. I doing this as root. Read this to understand, how it works. Linux CP/M tools manpages for commands important for as:

Note: CP/M emulator doesn't like, when disc content is changed outside. So before using Cpmtools commands, use A:bye command to exit CP/M emulator and after doing Cpmtools work, use ./cpm2 to run it again.

Building and running an RTM/Z80 application on CP/M

Follow instructions in chapter Building and running an RTM/Z80 application on CP/M in RTM-Z80 User manual. I use drive J: for build things for CP/M emulated on Z80-SIM.

Create directories HTC309 and RTM-Z80_CPM in [homedir]/z80pack-1.37/cpmsim
Copy HiTech C Compiler 3.0.9 to directory [homedir]/z80pack-1.37/cpmsim/HTC309
Copy RTM-Z80-main/SOURCES + RESOURCES + DEMO to directory [homedir]/z80pack-1.37/cpmsim/RTM-Z80_CPM
Place xsub at 1st. line of make.sub and makelib.sub. Check if you have in config.mac:

	DEBUG	equ 0	;1=debug mode ON: verify task SP, task TCB, dealloc, lists, etc.
	SIM	equ 1	;1=Runs under Z80SIM, 0=Runs on RC2014(SC108+SC110)
	DIG_IO	equ 0	;1=RC2014 Digital I/O module is used
	CMD	equ 0	;1=CON CMD task is included
	RSTS	equ 0	;1=use RST for list routines (not for SIM)
	WATSON	equ 0	;1=Watson is used (not for SIM)
	C_LANG	equ 1	;1=Support for C language API
	IO_COMM	equ 1	;1=Support for async communications I/O
	SC108	equ 0	;1=SC108 is used (32KB ROM, 128KB RAM)
	MM	equ 0	;1=Memory Module is used (32KB ROM, 128KB RAM)
	M512	equ 0	;1=512KB ROM & RAM module is used (512KB ROM, 512KB RAM)
	BDOS	equ 1	;1=BDOS disk file support
	LPT	equ 0	;1=Parallel Printer (Compatibility mode)
	DYNM512	equ 0	;1=Extended dynamic memory support for M512 (set-it to 0 if M512=0)

Then copy (On Linux) content of [homedir]/z80pack-1.37/cpmsim/RTM-Z80_CPM + HTC309 to CP/M drive J:

cpmrm -f z80pack-hd ./disks/drivej.dsk *.* 

# Copy HiTech C compiler 3.0.9 to J:
cpmcp -f z80pack-hd ./disks/drivej.dsk HTC309/*.COM 0:
cpmcp -f z80pack-hd ./disks/drivej.dsk HTC309/*.OBJ 0:
cpmcp -f z80pack-hd ./disks/drivej.dsk HTC309/*.LIB 0:
cpmcp -t -f z80pack-hd ./disks/drivej.dsk HTC309/*.H 0:
cpmcp -t -f z80pack-hd ./disks/drivej.dsk HTC309/OPTIONS 0:

# Copy RTM-Z80 to J:
cpmcp -t -f z80pack-hd ./disks/drivej.dsk RTM-Z80_CPM/*.sub 0:
cpmcp -t -f z80pack-hd ./disks/drivej.dsk RTM-Z80_CPM/*.as 0:
cpmcp -t -f z80pack-hd ./disks/drivej.dsk RTM-Z80_CPM/*.h 0:
cpmcp -t -f z80pack-hd ./disks/drivej.dsk RTM-Z80_CPM/*.c 0:
cpmcp -t -f z80pack-hd ./disks/drivej.dsk RTM-Z80_CPM/*.mac 0:
cpmcp -f z80pack-hd ./disks/drivej.dsk RTM-Z80_CPM/*.hex 0:

On CP/M shell:

J>A:pip J:=A:xsub.com
J>A:submit make
J>A:submit makelib

J>c -iJ0: -o rtmdemo.c rand.as rt.lib

J>rtmdemo

Running an RTM/Z80 applications on RC2014

Follow instructions in chapter Running an RTM/Z80 application on RC2014 in RTM-Z80 User manual. I use drive I: for build things for RC2014 Pro with SC108 + SC102 + SIO/2. RTM/Z80 uses CTC channel #2. Recomended board is SC110 external link – Z80 Serial+CTC board. Because I use dedicated CTC (SC102) board, jumper on it must be set to feed ch. #2 from xtal Oscillator 7.3728 MHz. Also note that Interrupt-daisy-chain must be established between SIO/2 and CTC as described above.

Create directory RTM-Z80_RC2014 in [homedir]/z80pack-1.37/cpmsim
Copy RTM-Z80-main/SOURCES + RESOURCES + DEMO to directory [homedir]/z80pack-1.37/cpmsim/RTM-Z80_RC2014
Place xsub at 1st. line of make.sub and makelib.sub. Check if you have in config.mac:

	DEBUG		equ 0	;1=debug mode ON: verify task SP, task TCB, dealloc, lists, etc.
	SIM		equ 0	;1=Runs under Z80SIM, 0=Runs on RC2014(SC108+SC110)
	DIG_IO		equ 1	;1=RC2014 Digital I/O module is used
	CMD		equ 0	;1=CON CMD task is included
	RSTS		equ 1	;1=use RST for list routines (not for SIM)
	WATSON		equ 0	;1=Watson is used (not for SIM)
	C_LANG		equ 1	;1=Support for C language API
	IO_COMM		equ 1	;1=Support for async communications I/O
	SC108		equ 1	;1=SC108 is used (32KB ROM, 128KB RAM)
	MM		equ 0	;1=Memory Module is used, 0=SC108 is used
	BDOS		equ 1	;1=BDOS disk file support
	LPT		equ 0	;1=Parallel Printer (Compatibility mode) (not for SIM)
	;
	;	ROM/RAM options (only if SIM=0)
	;
	RAM128K		equ 1	;0=only 64K RAM, 1= 2 x 64K RAM available

Then copy (On Linux) content of [homedir]/z80pack-1.37/cpmsim/RTM-Z80_RC2014 + HTC309 to CP/M drive I:

cpmrm -f z80pack-hd ./disks/drivei.dsk *.* 

# Copy HiTech C compiler 3.0.9 to I:
cpmcp -f z80pack-hd ./disks/drivei.dsk HTC309/*.COM 0:
cpmcp -f z80pack-hd ./disks/drivei.dsk HTC309/*.OBJ 0:
cpmcp -f z80pack-hd ./disks/drivei.dsk HTC309/*.LIB 0:
cpmcp -t -f z80pack-hd ./disks/drivei.dsk HTC309/*.H 0:
cpmcp -t -f z80pack-hd ./disks/drivei.dsk HTC309/OPTIONS 0:

# Copy RTM-Z80 to I:
cpmcp -t -f z80pack-hd ./disks/drivei.dsk RTM-Z80_RC2014/*.sub 0:
cpmcp -t -f z80pack-hd ./disks/drivei.dsk RTM-Z80_RC2014/*.as 0:
cpmcp -t -f z80pack-hd ./disks/drivei.dsk RTM-Z80_RC2014/*.h 0:
cpmcp -t -f z80pack-hd ./disks/drivei.dsk RTM-Z80_RC2014/*.c 0:
cpmcp -t -f z80pack-hd ./disks/drivei.dsk RTM-Z80_RC2014/*.mac 0:
cpmcp -f z80pack-hd ./disks/drivei.dsk RTM-Z80_RC2014/*.hex 0:

On CP/M shell (run those commands one-by-one line, don't use copy/paste whole content):

I>A:pip I:=A:xsub.com
I>A:submit make
I>A:submit makelib

I have three scripts for building various demos, such as rtmdemo. On CP/M shell I run:

I>A:SUBMIT mymake1
I>A:SUBMIT mymake2
I>A:SUBMIT mymake3

On Linux shell:

cpmcp -f z80pack-hd ./disks/drivei.dsk 0:HEXBOOT.HEX hexboot.hex
cpmcp -f z80pack-hd ./disks/drivei.dsk 0:RTMDEMO.HEX rtmdemo.hex
cpmcp -f z80pack-hd ./disks/drivei.dsk 0:MSORT.HEX msort.hex
cpmcp -f z80pack-hd ./disks/drivei.dsk 0:TESTXR.HEX testxr.hex
cpmcp -f z80pack-hd ./disks/drivei.dsk 0:TESTXS.HEX testxs.hex
cpmcp -f z80pack-hd ./disks/drivei.dsk 0:TBDOS.HEX tbdos.hex
cpmcp -f z80pack-hd ./disks/drivei.dsk 0:GETXFILE.HEX getxfile.hex

Then use WinSCP to copy hexboot.hex and some program, e.g. rtmdemo.hex to your local directory. Open hexboot.hex and copy content to clipboard. Then switch to Putty connected to RC2014 and reset SC108. Make right-mouse-click over terminal to send content of hexboot.hex to RC2014. Type *gE000 and when you can see Ready to read RTM/Z80 HEX file do this same with rtmdemo.hex. Type dot . to omit breakpoint and Y to run demo external link .

Local Windows and remote Linux directory structure. Note: when you use WinSCP to upload C, H, AS, MAC, SUB and other from Windows to Linux - be sure that you have set Transfer setting as Text for those types.

Running own RTM/Z80 application on RC2014

I created simple demo application. Four independent tasks drive external link four Z80 PIO's.

On Linux shell (when CP/M is logged out using A:bye):

cpmrm -f z80pack-hd ./disks/drivei.dsk TESTPIOS.*
cpmcp -t -f z80pack-hd ./disks/drivei.dsk RTM-Z80_RC2014/testpios.c 0:

On CP/M shell I run I>A:SUBMIT mymake4.

On Linux shell:

cpmcp -f z80pack-hd ./disks/drivei.dsk 0:TESTPIOS.HEX testpios.hex

Next steps are the same as rtmdemo.

RC2014-CPM, te editor and other stuff

Ladislau Szilagyi created very interesting project, RC2014-CPM external link . This CP/M version is able to use SC108 or 512k ROM 512k RAM extended memory and some programs as HiTech C or te editor can use it.

I tried version for SC108 with RC2014 Pro. Here is some my experiences:

I had problems with CF cards. It was possible to format, but start CP/M lead to froze computer. I got advice, that old version 1.0 of CF module has compatibility issues. Fortunately I found that RC2014 Zed have new version 1.3 so I swapped CF modules between Pro and Zed.
It's necessary to have burned last SC108 firmware in SC108 ROM.
Then is necessary prepare CF card with CP/M 2.2
Next step is download 'te' sources and HI-TECH C with Ladislau enhancements.
Now apply SIO_PutSys_CF64_CPM_DA00H.hex or SIO_PutSys_CF128_CPM_DA00H.hex using SCM. Copy content to clipboard after boot and paste to terminal and then run it by *g8000
After this step, don't use putty with Cut/Paste, because stripped down CP/M is't interrupt driven and this leads to buffer overflow. Instead use Terraterm with 1ms delay after every chars.
Now we have 'stripped down' CP/M. Compile 'te' editor by running makete.sub and link by linkte.sub. BTW submit command on my system is crappy, so I run .SUB content line by line.
Finally is possible to run TE128.COM.

Compact Flash modules

CF cards

Preparing CF

Memory banks switching

te editor

Conclusion

RC2014 is amazing project. I had a lot of fun while building it and exploring possibilities of retrocomputing. That brought me back 30 years to 8 bit era when I built my first computer.

Finished RC2014 Pro. There is: Clock + SC108 [CPU-RAM-ROM] + DMA + CF + SIO/2 + 4 x PIO + CTC + WiFi + I/O.

RC2014 - Little Brother

Later I decided to build second small one - on BackPlane-5 external link + CPU + 512k ROM 512k RAM RomWBW + SIO/2 + 2 x CF + Digital IO. CPU and SIO/2 modules are gained from RC2014 Pro, where is SC108+SC104 modules now.

BackPlane-5 + modules

BackPlane-5 + 512kB RAM+ROM

both RC2014

RomWBW starting screen

512k ROM 512k RAM RomWBW Module

512k ROM 512k RAM external link has been designed to run RomWBW operating system on the RC2014 with a Z80 CPU. Due to the 64k of addressable memory limitation of the Z80, the memory in this module is divided up in to multiple 32k pages.

With RomWBW external link you can boot ROM based CP/M-80 2.2, Z-System or run MONITOR, BASIC, FORTH, play game or run custom ROM content.

Using two Compact Flash modules with RomWBW

Using two Compact Flash modules is little bit tricky. 1st CF is addressed on 0x10. If you have 2nd CF, it must use address 0x20. I solved it by routing pin #11 of 74LS138 decoder to 2nd card, where decoder isn't soldered. Because my BackPlane-5 is full, I stacked 2nd CF to 1st one.

Since we have added a second IDE interface, we will need to activate this interface using a custom ROM build:

Buy TL866II programmer
Install git, make, gcc, lib-ncurses.dev, srecord and g++ packages (I use Linux Debian)
mkdir RomWBW in your home directory
git clone https://github.com/wwarthen/RomWBW.git RomWBW
Modify RomWBW/blob/master/Source/HBIOS/cfg_rcz80.asm:

IDECNT		.SET	2		; IDE: NUMBER OF IDE INTERFACES TO DETECT (1-3), 2 DRIVES EACH
IDE1MODE	.SET	IDEMODE_RC	; IDE 1: DRIVER MODE: IDEMODE_[DIO|DIDE|MK4|RC]
IDE1BASE	.SET	$20		; IDE 1: IO BASE ADDRESS

cd RomWBW, run make command
Program RCZ80_std.rom to ST39SF040

With this change you can see this on startup screen:

IDE: IO=0x10 MODE=RC
IDE0: 8-BIT LBA BLOCKS=0x0001E900 SIZE=61MB
IDE1: NO MEDIA
IDE: IO=0x20 MODE=RC
IDE2: 8-BIT LBA BLOCKS=0x0001E900 SIZE=61MB
IDE3: NO MEDIA
PPIDE: IO=0x20 PPI NOT PRESENT

   A:=MD1:0
   B:=MD0:0
   C:=IDE0:0
   D:=IDE0:1
   E:=IDE0:2
   F:=IDE0:3
   G:=IDE2:0
   H:=IDE2:1
   I:=IDE2:2
   J:=IDE2:3

For accessing other drives, you need to use ASSIGN command. You can create .SUB file and use B:SUBMIT for it:

ASSIGN K:=IDE0:4
ASSIGN L:=IDE0:5
ASSIGN M:=IDE0:6
ASSIGN N:=IDE0:7
ASSIGN O:=IDE2:4
ASSIGN P:=IDE2:5

Note: Due to memory limit, ASSIGN drive P: fails to error: 'Disk buffer exceeded in CBIOS, aborted'.

Connecting to BBS

I use following approach to connect Wintermute BBS, which operates on rc2014.ddns.net:2014:

Because my Little Bro doesn't have free slot for official WiFi card, I use WEMOS D1 Mini
If you haven't Arduino IDE download and install it
Download Zimodem firmware
Open zimodem.ino with Arduino and near line 96 do following change:

# define RS232_INVERTED 0 // l.v.: was 1

Compile and upload to connected WEMOS module.
Use Serial monitor and after AT command you must get reply OK.
Then use AT+CONFIG and configure WiFi, and other options like this:

As you may see, I have Wintermute BBS stored in phone book under 123 number. Save changes and disconnect module.
Now is needed to remove FTDI chip from WEMOS - I used brute-force method with thin needle and soldering iron. Of course now is not possible to upgrade firmware.
Get WEMOS universal shield and solder two 10k/22k voltage dividers for RX and CTS signals. It's the same approach as R2/R3 used in official WiFi module. Alternatively it's possible to use MOSFET Level Converter.
Stack both boards together and make connection to SIO/2 module port B. Note that 5V must be linked to connector using JP3 jumper on SIO/2 board. So SIO/2 🡺 ESP module:
- GND 🡺 GND
- RTSB 🡺 Digital pin #5 (CTS)
- 5V 🡺 5V
- RXB 🡸 TX
- TXB 🡺 RX
- unconnected
Start Qterm - QTERM82.COM. Use ^Y ? and you will see Help message.
Reset WEMOS and wait for message which informs you that WiFi is connected. Use ATD123 and if everything is OK, you will be connected to BBS.

Extending Little Bro

Now my RC2014 Little Brother is extended with second BackPlane-5. There is another Digital I/O module and two modules for LED matrixes.

8x8 LED matrixes with MAX7219

Driver module

12x8x8 LED Matrix

I have ported Arduino MaxMatrix library external link for driving 8x8 LED matrixes with MAX7219 to HI-TECH C Compiler syntax. Driver board uses 74HCT374 - circuit is same as official I/O board. There are also four two-color LED's for easier debugging.

NeoPixel Module – 8×8 Matrix"

This is absolutely awesome module external link . It contains 8x8 RGB LED matrix. I have extended it with second matrix.

Snake game driven by joystick. It allows create extra apples and speed-up by buttons.
Neodie demo from SDK
My Sprites demo
Breakout from SDK extended to two matrixes
Ping-Pong

Board delivery	Board completed	Breakout	Neodie
R sprite	Hearts	Joystick	Snake game

For compiling ASM and C sources I use Z88dk external link which works perfectly. If you are interested about source code, feel free to contact me.

YM2149 Sound Card

This module external link . is based around the YM2149 / AY-3-8910 3 channel sound chip. It's supported by RomWBW, but similarly as with two CF cards, there is needed to build custom ROM. It's not absolutely necessary, most applications have own support for chip. So if you want it, follow those intstructions but use this modifications in source code:

Modify RomWBW/blob/master/Source/HBIOS/cfg_rcz80.asm:

AY38910ENABLE	.EQU	TRUE		; AY: ENABLE AY-3-8910 / YM2149 SOUND DRIVER
AY_CLK		.EQU	1843200		; AY: PSG CLOCK FREQ, ASSUME 7.3728 MHz / 4
AYMODE		.EQU	AYMODE_RCZ80	; AY: DRIVER MODE: AYMODE_[SCG|N8|RCZ80|RCZ180|MSX|LINC|MBC]

And also modify RomWBW/blob/master/Source/HBIOS/Config/RCZ80_std.asm:

AY38910ENABLE	.SET	TRUE		; AY: AY-3-8910 / YM2149 SOUND DRIVER
AYMODE		.SET	AYMODE_RCZ80	; AY: DRIVER MODE: AYMODE_[SCG|N8|RCZ80|RCZ180|MSX|LINC]

For playing music is possible to use TUNE application external link . I have created PingPong that uses sound card. Two 8-bit I/O ports on AY-3-8910 are utilized for joysticks.

Board with joystick

Starting screen

Playing

Score

Conclusion

Now RC2014 Little Brother is ready to discover possibilites of 8-bits retrocomputing.

Ukraine Red Cross Fundraiser RC2014 Zed

My 3rd one is RC2014 Zed Fundraiser kit for Red Cross Ukraine.

DS1302 RTC Module

On RC2014 Zed I have DS1302 Real Time Clock Module external link . It is based around the DS1302 chip and is supported using RomWBW.

Bubble Display Module

Another interesting module is 7 Segment Bubble LED Display external link . You can play with it with some various programs in different languages.

Bubble Display Kit

Digital Clock

I wrote FizzBuzz sample external link . My another program utilizes both RTC and Bubble Display Modules to turn RC2014 to digital clock.

RC2014 Mini

My (I hope definitely) last one is Mini external link with CP/M Upgrade Kit . I have extended it with BackPlane-5.

Delivery

Extending

Running

PicoTerm

RC2014 Pi Pico VGA Terminal

RC2014 Pi Pico VGA Terminal external link is a simple terminal for the RC2014 to allow it to be used standalone. It connects to a regular VGA monitor and accepts a USB keyboard.

8×8 LED Matrix Display Module

This module external link contains one 8x8 LED matrix.

Delivery

Building

Running

Original Zilog documents

Mario Blunks tutorial set

How To Program the Z80 Periphery Tutorial (How to program the z80 SIO)
How To Program the Z80 Periphery Tutorial (How to program the z80 CTC)
How To Program the Z80 Periphery Tutorial (I²C programming using the Z80 PIO)

Ken Shirriff's blog

This blog contains interesting informations about Z80 CPU internals.

Learning algorithms

Z80 advanced math
Retro Programming
Programiz - Learn to Code for Free
BeginnersBook.com – Tutorials For Beginners

Other

bramm.dk blog
Visual Z80 remix
Z80 CPU timing explained
A new cycle-stepped Z80 emulator My own experiences with it:

My own things

RC2014 Images gallery
Some videos with my RC2014 in action
Assembler sources - playing with LED's, etc... for TASM
Assembler source for ZAS - HI-TECH SOFTWARE Z80 Macro Assembler
Assembler sources - for Z80 Simulator IDE
C sources collection for learning algorithms like sorting, primes, factorial, etc...
C sources and other things for RTM/Z80
BASIC sources collection
Photo gallery

My RC2014 - Z80 Homebrew Computers

Introduction - RC2014 Pro

Assembling

Aditional modules

Digital I/O board

Z80 PIO, Z80 CTC

Z80 SIO/2

WiFi module

Z80 DMA

SC108 – Z80 CPU, ROM and RAM module

Running CP/M 2.2

MBASIC

Developing software in assembler

Editing ASM, AS and C sources

TASM Development environment

ZAS Development environment

Transfering files from PC to RC2014

Z80 Simulator IDE

HI-TECH C Compiler 3.09 for CP/M

Building and running AES-256 demo

HI-TECH C Compiler 3.09 with emulator

Using inline assembler in C sources

DX-Forth (with emulator)

Borland Turbo Pascal

Borland Turbo Modula

Digital Research PL/I Compiler for CP/M-80

Micro Focus COBOL for CP/M 2.2

MicroPro office software

Games

RTM/Z80 - Retro Tiny Multitasking system for Z80

Z80-SIM

Cpmtools 2.21

Building and running an RTM/Z80 application on CP/M

Running an RTM/Z80 applications on RC2014

Running own RTM/Z80 application on RC2014

RC2014-CPM, te editor and other stuff

Conclusion

RC2014 - Little Brother

512k ROM 512k RAM RomWBW Module

Using two Compact Flash modules with RomWBW

Connecting to BBS

Extending Little Bro

8x8 LED matrixes with MAX7219

NeoPixel Module – 8×8 Matrix"

YM2149 Sound Card

Conclusion

Ukraine Red Cross Fundraiser RC2014 Zed

DS1302 RTC Module

Bubble Display Module

RC2014 Mini

RC2014 Pi Pico VGA Terminal

8×8 LED Matrix Display Module

Links

Original Zilog documents

Mario Blunks tutorial set

Ken Shirriff's blog

Learning algorithms

Other

My own things