Software for Bill Shen's Z280RC Single Board Z280 system on a RC2014 board
This repository contains a snapshot of the original software, plus enhancements, updates and new utilities for Bill Shen's Z280RC single board Z280 system - as described on the RetroBrew builders wiki at
https://www.retrobrewcomputers.org/doku.php?id=builderpages:plasmo:z280rc
The original software is located in zip files in the "original" subdirectory.
My modifications to Bill Shen's original non-banked CBIOS3 for CP/M 3 are in the "system/cpm3-nonbanked" subdirectory - adding DS1302 clock support.
I've also developed
-
A modified CP/M 2 (in system/cpm22) to support file partitions containing up to 2048 directory entries (four 8Mb drives on CompactFlash with 1.5Mb RAMdisk);
-
A CP/M 3 BIOS (in system/bios280) supporting Banked memory (up to eight banks of memory, four (and optionally eight) 8Mb drives, 1.5Mb RAMdisk, optional 4-port QuadSer module);
-
Ported UZI280 (in system/uzi280*) - a version of the Unix operating system; and
-
Some new utility programs in the "utilities" subdirectory - XMODEM, RESET, TIME, DU, NULU, RELHEX and updated for CP/M 3 versions of DEVICE, HELP and KERMIT.
Minor tweak to XMODEM to look for its configuration file on the system drive (in A:XMZ280RC.CFG). Be sure to set this with the SYS attribute so it is seen from all user areas under CP/M 3.
A>set xmz280rc.cfg [sys ro]
Ported the Z280 UART console I/O routines to the latest version of Martin Eberhard's XMODEM version 2.9. The new version is in the "utilities" subdirectory as a ZIP file utilities/xm29z280.zip or you can download the individual files utilities/XM29Z280.MAC, utilities/XM29Z280.HEX and utilities/XM29Z280.COM . This version uses the same configuration file utilities/XMZ280RC.CFG as the previous version (see below) to obtain its default switch values (/X3 uses the built-in Z280 console UART).
A new utility program to reset the system from CP/M back to the ZZmon command prompt. (This is the software equivalent of pressing the reset button).
Assembler source is in utilities/RESET.MAC and a pre-built binary is in utilities/RESET.COM
The CP/M 3 BIOS checks for the presence of a QuadSer module. If none is found then it reports
%QUADSER I/O board not detected
during the system start-up, and it disables the TTY0 to TTY3 devices.
However, the default character device assignments for both the AUXIN and AUXOUT devices were not adjusted (causing an error if you tried to use the DEVICE command).
To fix this, I've changed the defaults for the AUXIN and AUXOUT to the NULL device. This means if you have a QuadSer module, then you will now need to use the DEVICE command (in the PROFILE.SUB start-up file) to configure the AUXIN and AUXOUT devices under CP/M 3. For example -
C>device aux:=tty2[19200,xon]
A:DEVICE COM (User 0)
Physical Devices:
I=Input,O=Output,S=Serial,X=Xon-Xoff
UART NONE IOS TTY0 19200 IOS TTY1 19200 IOS
TTY2 19200 IOSX TTY3 19200 IOS
Current Assignments:
CONIN: = UART
CONOUT: = UART
AUXIN: = TTY2
AUXOUT: = TTY2
LST: = Null Device
C>
To set them back to NULL, use
C>device auxin:=null, auxout:=null
A:DEVICE COM (User 0)
Physical Devices:
I=Input,O=Output,S=Serial,X=Xon-Xoff
UART NONE IOS TTY0 19200 IOS TTY1 19200 IOS
TTY2 19200 IOSX TTY3 19200 IOS
Current Assignments:
CONIN: = UART
CONOUT: = UART
AUXIN: = Null Device
AUXOUT: = Null Device
LST: = Null Device
C>
In addition, I have verified that my CP/M 2, CP/M 3 and UZI280 (and Hector Peraza's RSX280) operating systems all work under the new Z280RC emulator by Michal Tomek.
The emulator (which runs under Linux/macOS and Windows MinGW) is available from
https://github.com/mtdev79/z280emu
Note that the UZI280 operating system still needs to be loaded from CP/M and not yet from the ZZmon monitor -
C>bootuzi
C:BOOTUZI COM
UZI280 is (c) Copyright (1990-96) by Stefan Nitschke and Doug Braun
boot: 0
UZI280 version 1.12
login: root
[root]/usr/root#
I'm working on adding support for the QuadSer module and direct boot capability from ZZmon to UZI280 and a CP/M RESET utility (to restart back to ZZmon).
They'll be added here soon.
Change the CP/M 2 cold-boot default drive to B: (since this is where the CP/M 2.2 system files are loaded). Updated only the "BIG" version of the CPM22BIG.MAC monolithic source file - and there's a new Intel HEX loader file for CPM22BIG.HEX in the system/cpm22 subdirectory. No more "REQUIRES CP/M 3" messages when you type a "PIP" command! (and a warm-boot returns to the current selected default drive).
Please note: The CP/M 3 system images I've made available are linked with Simeon Cran's ZPM3 replacement BDOS routines.
ZPM3 is a Z80 coded CP/M 3 compatible BDOS replacement which includes
-
Bug fixes (the "Random Read Bug" and System Control Block sanity checks),
-
Enhancements to the BDOS Parse (Function 152) to accept drive/user area filespecs (like C1:FILE.DAT),
-
New functions for file time-stamps manipulation - Get Stamp (Function 54), Use Stamp (Function 55) can retrieve and change a file's time-stamp, and
-
Command-line history and WordStar(C)-style editing for Read Console Buffer (Function 10).
You'll find more details here and I've added the ZPM3 distribution archive (includes sourcecode) in the system/zpm3/ZPM3S.ARC file.
If you wish to revert to the Digital Research CP/M 3 BDOS, you'll need to select it with the DRI-CPM3.SUB file and rebuild a new CPM3.SYS file (e.g. using the BIGBIOS.SUB build procedure from the BIOS source area).
I updated the CP/M 3 disk image to include the CP/M 2.2 BIOS sources (on drive B: user area 1), and included Infocom games and terminal set-up program (on drive D: in user area 0). Also, updated the IDEHD.MAC CompactFlash driver module to match the latest version.
Get it from z280rc-bigcpm-swab.img.gz
There's now an updated CP/M 3 banked memory system supporting 2048 directory entries on the A: to D: drives (and if you require additional drives using the PARTN8 configuration option).
To be able to load CPM3.SYS from the revised drive layout, you'll need to install the new "BIG" CP/M 3 Loader from CPMLBIG.HEX onto the Z280RC's CP/M 3 boot area using ZZmon V2.3 by uploading this CPMLBIG.HEX Intel HEX file, and then write it to the boot track on the CompactFlash disk using the C3 command.
Next, you'll need to copy the CPM3BIG.SYS to the A: drive as CPM3.SYS, and install the CP/M 3 distribution files (be careful not to overwrite the new CPM3.SYS when you do this).
You can use cpmtools 'cpmcp' on a image file that's been transferred to a Windows, Linux or macOS system - using updated diskdefs from here, or by using the CP/M 2.2 system and XMODEM as detailed below
TinyZZ Monitor for Z280RC v2.3 18-Sep-2021
>Boot
1 - User Apps
2 - CP/M 2.2
3 - CP/M 3
4 - RSX280
5 - UZI280
Select: 2 Press Return to confirm:
Copyright 1979 (c) by Digital Research
CP/M 2.2 for Z280RC
20210918 w/2048 CF A:-D:
a>b:
b>pip xm.hex=con:[hz]
Send the Intel HEX load file for XMODEM from the XM27Z280.HEX file in ASCII mode to PIP. After a while, the b> prompt will appear, then load the HEX file to make XM.COM then download the XMODEM default configuartion file using xmodem protocol (send it using your comms program) from XMZ280RC.CFG -
b>load xm
FIRST ADDRESS 0100
LAST ADDRESS 10FF
BYTES READ 1000
RECORDS WRITTEN 20
b>xm xmz280rc.cfg /r/c/x3/z9/q
Now you have a working XMODEM (XM) command, use it to transfer files to the CP/M drive. You'll only need to use the /r (receive) or /s (send) options and maybe the /c (crc/checksum mode) from now on, if you have the XMZ280RC.CFG file on the current drive.
To save you some time, I have prepared an image of my CompactFlash CP/M drive partitions (A: thru D:) which is populated with a large range of software (compilers like Hi-Tech C, FORTRAN-80, BASIC-80, COBOL-80, RML ALGOL, TurboPascal plus the Z3PLUS Z-System and various editors and assemblers. The CP/M 3 BIOS source files are on drive C in user area 1.
Download the gzip'ed image from z280rc-bigcpm-swab.img.gz uncompress it with gunzip then write it to your blank 128Mb or 256Mb CompactFlash card using dd with the byte-swap option.
For example (when /dev/sdX is the CompactFlash device name under Linux)
gunzip z280rc-bigcpm-swab.img.gz
sudo dd if=z280rc-bigcpm-swab.img of=/dev/sdX bs=512 count=65536 conv=swab
(substitute for /dev/sdX as appropriate on your system).
The changes I made to CP/M 2.2 to support 2048 directory entries (instead of the original 512 directory entries) seem to be working.
I've updated the system/cpm22/CPM22ALL.MAC file to include a symbol definition to enable this. Just change the symbol DE2048 to -1 and rebuild a new Intel HEX loader file (as I outlined below).
For your convenience, I've included CPM22BIG.HEX that you can load into ZZmon V2.3 (see below), then write this to a NEW or SPARE CompactFlash card.
WARNING: THIS CHANGES THE CP/M DISK DIRECTORY AND FILE ALLOCATION ON EACH OF THE CP/M PARTITIONS - so don't do this to your previous working CompactFlash card.
In addition to supporting a larger number of files, I've altered the disk allocation to use the previously unused track 63 on each of the A:, B:, C: and D: partitions. The latter three are now 8192 Kilobytes, while the A: drive has 1 reserved track for the system boot loaders (it is 8064 Kb).
Once you have uploaded CPM22BIG.HEX and issued the C2 command to write the new CP/M 2.2 image to the boot track, format each of the drives on your NEW CompactFlash drive using the XA, XB, XC, XD (and XE to clear the RAMdisk). Now you can proceed to load the CP/M 2.2 programs onto the RAMdisk (drive E:) from the CPM22DRI.HEX file.
TinyZZ Monitor for Z280RC v2.3 18-Sep-2021
>Boot
1 - User Apps
2 - CP/M 2.2
3 - CP/M 3
4 - RSX280
5 - UZI280
Select: 2 Press Return to confirm:
Copyright 1979 (c) by Digital Research
CP/M 2.2 for Z280RC
20210918 w/2048 CF A:-D:
a>b:
b>dir
No file
b>e:
e>dir
E: ASM COM : BIOS ASM : CBIOS ASM : DDT COM
E: DEBLOCK ASM : DISKDEF LIB : DUMP COM : DUMP ASM
E: ED COM : LOAD COM : MOVCPM COM : PIP COM
E: STAT COM : SUBMIT COM : SYSGEN COM : XSUB COM
e>pip b:=e:*.*[v]
COPYING -
ASM.COM
BIOS.ASM
CBIOS.ASM
DDT.COM
DEBLOCK.ASM
DISKDEF.LIB
DUMP.COM
DUMP.ASM
ED.COM
LOAD.COM
MOVCPM.COM
PIP.COM
STAT.COM
SUBMIT.COM
SYSGEN.COM
XSUB.COM
e>b:
b>stat b:
Bytes Remaining On B: 8004k
b>stat b:dsk:
B: Drive Characteristics
65536: 128 Byte Record Capacity
8192: Kilobyte Drive Capacity
2048: 32 Byte Directory Entries
0: Checked Directory Entries
256: Records/ Extent
32: Records/ Block
1024: Sectors/ Track
64: Reserved Tracks
b>
Next up, I'll do the CP/M 3 system updates... stay tuned!
In preparation for increasing the number of directory entries on the CP/M CompactFlash drives A: to D:, I have uploaded my modified source-code for CP/M 2.2 that can be built using Hector Peraza's ZSM4 Macro Assembler. This also contains a (minor) fix to the RAMdisk size to match the Z280RC's memory (Bill Shen's original source was for the TinyZ280 which supported larger SIMM72 DRAM modules, whereas the Z280RC has 2Mb of static RAM).
To assist with the generation of a CPM22ALL.HEX in Intel HEX loader format, I've added a RELHEX utility that converts the assembler's .REL output file into .HEX to the utilities subdirectory. You'll find the source for RELHEX12.MAC here, and a compiled CP/M binary) here.
To prepare CPM22ALL.HEX from the source in CPM22ALL.MAC use commands like -
ZSM4 =CPM22ALL
RELHEX12 CPM22ALL
To install this, you may wish to grab and install the latest ZZmon2 monitor V2.3 from Hector Peraza's GitHub repository at https://github.com/hperaza/ZZmon2, clear memory using the Z command, then upload CPM22ALL.HEX to the running monitor. Finally, copy it to the CP/M 2 boot sectors using the C2 comand. For example -
TinyZZ Monitor for Z280RC v2.2 17-Sep-2021
>Zero memory
Press Return to confirm:
>
Now send the Intel HEX file in ASCII mode. You should see a few rows of dots like
>..............................................................................
...............................................................................
...............................................................................
...............................................................................
...............................................................................
.................................0X
>Copy to CF
0 - Boot & ZZmon
1 - User Apps
2 - CP/M 2.2
3 - CP/M 3
Select: 2 Press Return to confirm:
>Boot
1 - User Apps
2 - CP/M 2.2
3 - CP/M 3
4 - RSX280
5 - UZI280
Select: 2 Press Return to confirm:
Copyright 1979 (c) by Digital Research
CP/M 2.2 for Z280RC
20180727 1.5 meg RAMdisk
a>
I'll post the new 2048 directory entry modifications in the next few days (after I test them out).
I've included my cpmtools diskdef file entries in the "utilities" subdirectory. This allows you to perform file copies and manipulations to an image file of the Z280RC's CompactFlash CP/M file partitions using the cpmtools utilities on Windows, macOS and Linux.
Please note that you need to create or write images that have the bytes swapped (the Z280RC interface has the bytes written in big-endian order). The Linux 'dd' command has a 'conv=swab' option that does this.
The definition file can be downloaded from here.
After adding these entries to the system's diskdefs file you can manipulate disk images by specifying the '-f z280rc-X' format (where X corresponds to the CP/M drive letter in lower case).
For example, from macOS or Linux -
# Copy CP/M partition from CompactFlash mounted on the device /dev/sda
sudo dd if=/dev/sda of=z280rc-cf.img bs=512 count=131072 conv=swab
# list the CP/M directory of the B: drive partition
cpmls -f z280rc-b -l z280rc-cf.img
[directory of B: partition omitted]
# copy a file to the CP/M E: drive in user area 10
cpmcp -f z280rc-e z280rc-cf.img filename.txt 10:FILE.TXT
# To write it back to CompactFlash use -
#
sudo dd if=z280rc-cf.img of=/dev/sda bs=512 count=131072 conv=swab
This is just a note about the way I set-up CP/M 3 on my Z280RC.
You might have noticed that I set the default login disk as drive C:. This is mainly as a convenience - as this is my working directory. You can change this using the GENCPM program when you do a system generation by answering the question with your desired default (some people like it to be A:) -
C>gencpm
A:GENCPM COM (User 0)
CP/M 3.0 System Generation
Default entries are shown in (parens).
Default base is Hex, precede entry with # for decimal
Use GENCPM.DAT for defaults (Y) ?
Create a new GENCPM.DAT file (N) ? y
Display Load Map at Cold Boot (Y) ?
Number of console columns (#80) ?
Number of lines in console page (#24) ?
Backspace echoes erased character (N) ?
Rubout echoes erased character (N) ?
Initial default drive (C:) ? a:
...
(answer all remaining prompts with Return key)
Also, since this is the default drive upon booting, you'll need to place a copy of SUBMIT.COM on this drive so you can use a PROFILE.SUB file to tweak the system search path and device settings after boot-up.
If you have the CP/M 3 system files on drive A: then make these accessible from all user area and drives by ensuring they have the SYS attribute (and read-only if you're extra cautious). Do this using -
C>a:set a:*.com [sys ro]
C>a:set a:help.hlp [sys ro]
(also you may wish to include various libraries and programming header files) and then
C>a:pip c:=a:submit.com[r
Finally create a PROFILE.SUB like the following (create this with an editor if you prefer). As you see, I set my search path to use the current drive, the RAMdisk, drive C: and finally drive A:. I also copy the XMODEM configuration file to each disk in user 0 so I don't have to specify the parameters to force it to use the console UART.
C>a:pip c:profile.sub=con:
; C:PROFILE.SUB
;
; XMODEM default configuration to M:
a:pip m:=a:xmz280rc.cfg[wrg0]
a:set m:xmz280rc.cfg [sys ro]
; Search path is current drive, RAMdisk, drive C and drive A
a:setdef * m: c: a: [order=(com,sub) display page uk temporary=m]
; Use QuadSer port TTY3 at 115200 bps for Kermit (using the AUX: device)
a:device aux:=tty3[115200]
a:date
^Z
C>
(That last line is a Ctrl-Z to end the file).
With the system set-up like this, I no longer need to specify the disk drive to run a program. Also, configure programs like TurboPascal and WordStar with their SETUP programs to load their overlays etc from drive A: too.
Included a copy of CP/M KERMIT V4.11 (configured for CP/M-Plus) so you can test the QuadSer ports. KERMIT.COM is available in the utilities subdirectory (or click the link).
Just set the AUX: port assignment and baud rate prior to running KERMIT using the DEVICE command (see below). When you use KERMIT's connect command, what you type will be sent out the QuadSer port, and any received characters will be displayed on the console. If you connect the port to another computer capable of running its version of kermit in server mode, you will be able to transfer files using KERMIT's get and send commands.
Further details (and sourcecode) for KERMIT can be downloaded from http://www.kermitproject.org/archive.html#cpm80
Built a modified version of the CP/M-Plus DEVICE utility to support substituted baudrates. The new version will accept 28800, 38400, 57600 and 115200 as speed values. The modified PL/M-80 sourcecode, DEVICE.COM as well as updated CP/M Plus HELP.HLP (and source in HELP.DAT) are in the utilities subdirectory.
Just copy DEVICE.COM and HELP.HLP to your system drive and set them with the SYS attribute to make them available.
A>device tty3[115200
A:DEVICE COM
Physical Devices:
I=Input,O=Output,S=Serial,X=Xon-Xoff
UART NONE IOS TTY0 19200 IOS TTY1 19200 IOS
TTY2 19200 IOS TTY3 115K2 IOS
Current Assignments:
CONIN: = UART
CONOUT: = UART
AUXIN: = TTY3
AUXOUT: = TTY3
LST: = Null Device
A>
Also, I added some notes regarding a hardware modification to the QuadSer 4-port module that prevents spurious interrupts from floating inputs on the serial Rx pins of each port. You'll find it in the QuadSer-notes folder with a README and photo (courtesy of Hector Peraza) of the mods.
And finally, I included an application note PDF retrieved from the Oxford Semiconductor pages on the Wayback machine. These were useful to me when I was writing the drivers for the OX16C954 4-port UART chip.
Added CP/M Plus support for Bill Shen's QuadSer Rev1 4-port UART module in RC2014 form-factor.
This is a UART module using the Oxford Semiconductor Ltd. OX16C954 rev B chip with 128-byte FIFOs for each receiver and transmitter. It has 4 independent UART ports with program selectable baud rates between 50 and 115200 bps in a variety of framing formats. Higher speeds are also possible - but not implemented for CP/M-Plus.
For hardware details see Bill Shen's pages at
https://www.retrobrewcomputers.org/doku.php?id=builderpages:plasmo:quadser:ec4z280rc
The configuration files now contain a "quadser" equate that you set to "true", along with a "use$device$io" equate to enable this support.
The current implementation uses polled I/O (and I intend to add support using interrupts soon).
With "quadser" enabled, four additional serial devices named TTY0, TTY1, TTY2 and TTY3 will be enabled. You can assign one or more of these to the console (CON:), auxiliary (AUX:) or printer device (LST:) using the DEVICE command. Speed settings can also be adjusted (see below).
For example, to specify TTY3 as the AUX device at 9600 bps use
A>device aux:=tty3[9600]
or to have the console input and output simultaneously on two devices (e.g. the Z280's UART and TTY0 at 19200 bps with XON/XOFF flow control) use
A>device con:=uart,tty0[19200,xon]
Since CP/M Plus was released, it is now common to use higher speeds than the 19200 bps maximum that the DEVICE command and internal CP/M data structures allow. Therefore I have substituted four of the less common data rates as follows -
CP/M Old Now
75 28800
134 38400
150 57600
1800 115200
Until I produce a modified CP/M Plus DEVICE program, you can specify higher speeds by using the corresponding old value on a DEVICE command.
For example, to use TTY3 at 115200 bps use -
A>device tty3[1800]
A:DEVICE COM
Physical Devices:
I=Input,O=Output,S=Serial,X=Xon-Xoff
UART NONE IOS TTY0 19200 IOS TTY1 19200 IOS
TTY2 19200 IOS TTY3 1800 IOS
Current Assignments:
CONIN: = UART
CONOUT: = UART
AUXIN: = TTY3
AUXOUT: = TTY3
LST: = Null Device
A>
Pre-built versions of the various banked configurations can be found in the system/bios280 subdirectory.
You can also download all the CP/M Plus BIOS files in the following ZIP file -
https://github.com/agn453/Z280RC/blob/master/system/bios280/bios280.zip
Fixed some erratic date/time setting under CP/M-Plus.
I've tweaked the DS1302 time-keeping chip routines in the BIOS CLOCK module (and the TIME.COM utility) to adjust the read/write timing to use a more accurate 1 microsecond serial timing for the 3-wire interface.
I found the original DU-V88.LBR of Ward Christensen's Disk Utility (better late than never) and added it to the "utilities" subdirectory
Some more tinkering with I/O page selection, interrupt routine and word address alignment. Also I found the missing .tar file with HiTech C header files and the UZI280 system libraries. I've put this UZISYTAR.LBR in system/uzi280-usrtar with the other .LBR files that can be extracted and written to the UZI partition using the XFRSYTAR.SUB submit file. When you boot UZI280 you'll need to extract this tar file below the root directory using
/bin/sh
cd /
/bin/tar xvf /Tapes/uzi112s.tar
The HiTech C compiler now works.
/bin/sh
cd /usr/root
cat >hello.c <<EOF
#include <stdio.h>
main()
{
printf("Hello world from UZI280 on the Z280RC!\n");
}
EOF
cc hello.c
./hello
I also added some utilities to the MKBOOT.SUB and COPYALL.SUB submit files
in the system/uzi280-xutils directory. This allows an UZI system partition
for system recovery to be created (on either /dev/wd1 or /dev/wd2). When
you run (say) MKBOOT.SUB you'll need to specify a parameter to select the
partition. Use "2" for /dev/wd1 or "3" for /dev/wd2. After running this
you can BOOTUZI and answer the boot: prompt with 2 or 3 (instead of 0) to
start the corresponding partition, Login as root and do a file system check
on the other (non-mounted) partitions - e.g. fsck /dev/wd0 to check the
primary UZI partition. You can also create mount-points and mount the other
file systems for backup purposes -
/bin/sh
mkdir /disk0
mount /dev/wd0 /disk0
cd /disk0; tar cvf /Tapes/backup-wd0.tar .
umount /dev/wd0
I've implemented support for the DS1302 timekeeper chip in UZI280 to set the time-of-day and fixed an issue with I/O page selection affecting maskable interrupts in my CompactFlash device support routine (IDECF.AS). You can fetch MACHDEP.C MACHASM.C and IDECF.AS from system/uzi280-kernel/ and re-compile the kernel using MAKE - or download the UZIKERNL.LBR file again to get the complete kit of kernel build files. Fixing the aforementioned issues has introduced another problem with the UZI280 "ps" command which was previously working but now gives a "Can't read /dev/kmem: Error 0" which I am investigating.
Also, a couple more UZI280 binary tar files for the HiTech C compiler (uses CPM emulation) and "User Binaries" have been added to system/uzi280-usrtar as well as in the CP/M library files UZICTAR.LBR and UZIUSTAR.LBR. Under CP/M use NULU to extract the two .tar files and execute the XFRCTAR.SUB and XFRUSTAR.SUB to transfer them to the /Tapes directory on the UZI file system partition. Extract these files under UZI280 using a command like the following -
/bin/sh
cd /
/bin/tar xvf /Tapes/uzi112c.tar
/bin/tar xvf /Tapes/uzi112u.tar
Added UZI280 binaries to system/uzi280-bintar/UZIBNTAR.LBR. Use the XFRBNTAR.SUB submit file to transfer these to the /Tapes directory on the UZI filesystem partition, then boot up UZI280, login as root (no password) and extract the tar files using something like the following
/bin/sh
cd /bin; for f in /Tapes/bin_0*.tar; do /bin/tar -xvf $f; done
CP/M utilities for manipulating library archives (.LBR files) and Disk Utility V8.8 (suitable for accessing the CP/M-Plus disk drive partitions and sector view/editing) have also been added to the utilities folder as NULU.COM and DU.COM
I've managed to modify the UZI280 operating system to boot up on the Z280RC. There's been a few hiccups along the way (mainly dealing with a mixture of word-count and byte-count DMA transfers) and the requirement for using a modified version of the HiTech C V3.09 compiler and Z280 library routines to build the system. I based my modifications on the UZI280 source code V1.12 for the Tillman Reh CPU280 system from http://oldcomputers-ddns.org/public/pub/rechner/zilog/z280/uzi280/index.html
My modified sources are in the system/uzi280-kernel and system/uzi280-xutils folders. There are two CP/M library files UZIKERNL.LBR and UZIXUTIL.LBR that can be transferred and extracted (using NULU.COM under CP/M-Plus) to different drives/user areas (I use E0: for the kernel files, F0: for the CP/M Utilities). A MAKEFILE in each can be used to build the libraries and UZI system image using the MAKE command. XUTILS.SUB will build two CP/M utilities MKFS and UCP for creating a UZI partition and copying files from CP/M. The log-file system/kernel/UZIBUILD.LOG is a transcript of the build process and start-up.
Still to-do is to copy the utilities and CP/M emulator onto the UZI partition.
Squeeze a few more bytes from common memory. Add a CLOCK$50HZ setting to select between the 50Hz interrupt heart-beat clock using C/T 0 & C/T 1 cascaded (see below) and a 128Hz clock using only Counter/Timer 0.
Implement and test Z280 on-chip device interrupts with a 20ms heart-beat counter (a single word counter at BIOS+063h) using cascaded Counter/Timer 0 and 1. These operate in timer mode and an interrupt is generated at 50Hz. Enable this by setting both INT$ENABLED and USE$TIMER$INTERRUPT in the configuration file (CONFINT8.LIB has this enabled). Also removed the dual banked testing version (CPM3BNK1.SYS) - but you may still generate it if required using the BNK1BIOS.SUB submit command file.
Updated the DS1302 timekeeper chip TIME program (in the utilities directory) to support a Banked system (this makes adjusting the time-of-day easier than using the CP/M-Plus DATE command).
Interrupt and Trap handling using Interrupt Mode 3 has been tested for System Calls and error traps (divison by zero, divide quotient exceptions, and memory access violations). Device interrupts are not yet implemented. Set the INT$ENABLED equate to TRUE to enable this in the configuration file (CONFINT8.LIB is supplied with DEBUG still enabled). CPM3INT8.SYS is a bootable system image with this feature active.
Squeeze as much as possible out of the Banked system common memory to maximise the size of the CP/M transient program area - resulting in 61KB free for user programs. There's a new configuration setting to remove the Character I/O device support in BIOSKRNL and CHARIO modules. I've defaulted USE$DEVICE$IO to FALSE to only use the Z280 UART console (and free up common memory).
Also clean-up the conditional code to build a CPMLDR3.HEX loader. Now the settings in the CONFLDR.LIB configuration correctly build the aforementioned loader that you can write to the CompactFlash boot tracks using the inbuilt ZZMON monitor. Just upload the Intel Hex format file directly (e.g. using the File menu Send file... option of Tera Term VT) and do a "C3" command to write it to the CP/M-Plus boot loader (sectors 1..15 of track 0).
Revised the banked memory layout to make the TPA and common memory contiguous. The DMAXFR routine now works properly (so you may choose to set USE$DMA$TO$COPY to TRUE to perform memory-to-memory transfers using the Z280's on-chip DMA controller instead of the Memory Management Unit). Coming up next... Interrupts and System/User mode operation.
I examined the DMAXFR code with a view to fixing the defect regarding transfers crossing the common memory address boundary. The modifications increase the size of the MOVE routine considerably (if I stick to the current physical-logical memory addressing configuration). I've therefore decided to not release updated DMA routines and instead will keep the memory management work-around in place for now. I may revise the memory allocation in future though (and make the transient program area and common memory contiguous). Do not set the USE$DMA$TO$COPY configuration item to TRUE in any of the configuration CONF*.LIB files for now.
USE$BIG$DRM now causes the extra drives E: thru H: to have 2048 directory entries (the maximum for the 4096 byte block size). Updated IDEHD.MAC and the CPM3*.SYS files. Also added a check for the maximum number of directory entries for a given block size in the CPM3M80.LIB macro library (a version of the Digital Research supplied CPM3.LIB that works with Microsoft's M80 and Hector Peraza's ZSM4).
Also added an initialisation routine to the RAMDISK module to prompt for and format drive M: if it doesn't have a valid CP/M directory label.
I was running out of space/directory entries so I built a version of Banked CP/M-Plus with eight 8MB CompactFlash drives. See the CONFBNK8.LIB, BANKED8.DAT, CPM3BNK8.SYS and BNK8BIOS.SUB files in the system/bios280 directory.
Depending on the actual size of CompactFlash you have, play it safe and use at least a 128MB one if you use this (64MB is not the same as 64MiB).
Drives E: thru H: are configured with 1024 directory entries each. A new configuration option USE$BIG$DRM enables 1024 directory entries (512 is the default for all other drives).
Hector Peraza's latest beta 11 of ZSM4 - a Z80/Z180/Z280 Macro-Assembler available at https://www.retrobrewcomputers.org/forum/index.php?t=msg&th=93&goto=3700&#msg_3700 found a typo in IDEHD which I fixed. Also went through and commented/ removed superfluous lines from the BIOS sources. No object code changes - just cosmetic!
Added a modified version of Martin Eberhard's XMODEM 2.7 (for file transfer via the console serial port). This now includes routines to drive the built-in Z280 UART directly. To select the internal routines use the /X3 switch on the XMODEM command line (or make it the default by having the XMZ280RC.CFG in the default directory). You'll find these files in the utilities folder or you can download a ZIP containing them directly from https://github.com/agn453/Z280RC/blob/master/utilities/xm27z280.zip
DMAXFR is not copying memory to memory when the source or destination physical address crosses one of the logical address bank boundaries. This is what has been causing interbank moves and disk I/O to fail when more than two banks have been configured. (Bank 0 and Bank 1 work because there is no difference between physical and logical addresses up to the common boundary in Bank 1 - i.e. 01DFFFF). The CP/M 3 PIP program was using memory across this boundary - hence why a copy with verify was failing for large files.
Anyhow, I've modified the MOVE and Disk I/O routines to use the MMU to shuffle data between Banks (using just logical addresses) and everything now works. The Banked configuration (CONFBANK.LIB and BANKED.DAT) now has Debugging disabled and is using Banks 1..3 with a 60KB TPA (CPM3BANK.SYS). I've left the Bank0/1 version with the debugger enabled (CONFBNK1.LIB and BANKED1.DAT resulting in CPM3BNK1.SYS) and the non-banked (CONFNBNK.LIB and NONBANK.DAT in CPM3NBNK.SYS).
I'll update the DMAXFR routine soon to remedy the problem (described above) shortly. In the meantime enjoy a Banked version of CP/M-Plus on the Z280RC!
PS; I've included a ZIP file containing all of the system/bios280 files as https://github.com/agn453/Z280RC/blob/master/system/bios280/bios280.zip to assist those not wanting to download the whole GitHub repository.
Added USE$DMA$TO$COPY configuration equate. If set to FALSE then extended memory moves using the BIOS MOVE routine will use the memory management unit to copy data from one bank to another. Using this setting I confirmed that the DMA transfers using the Z280's on-chip controllers were dodgy! I changed the DMAXFR routine in the BIOSKRNL module to in-line program the DMA channel without looping.
The Banked memory version using just bank 0 and 1 (CPM3BNK1.SYS) now seems to be working.
Added DEBUG capability to enter the debugger upon CTRL-P being typed at the console. Also made a special banked configuration that supports only two banks (bank 0 and 1) with directory hashing disabled and only a single directory and data buffer for each drive in bank 0. The resulting CPM3BNK1.SYS appears to be working (and I'm now convinced there's a problem with CP/M 3 PIP corrupting buffers).
Also added CPM3ADD2.MAC which (when assembled and linked) will show information about the running system's BIOS, SCB and disk drive data (DPH and DPB).
Updated disk modules to use hard-coded disk parameter headers and disk parameter blocks with internal disk allocation vectors (rather than letting GENCPM set these up). This is selectable via a USE$DISK$MACROS conditional equate in the CONF*.LIB files. Unfortunately, this had no effect on the PIP file copying verification error under the banked system. Non-banked and Loader configurations work fine!
My own version of a CP/M Plus BIOS for the Z280RC are in the "system/bios280" subdirectory.
There are submit files that build Non-banked (working), Banked (still has problems - see below*) and Loader .COM files (not yet integrated into the boot loader track on the CompactFlash drive).
The Y2K patched versions of the system page relocatable BDOS modules for CP/M 3 and the ZCPM3 system page relocatable compatible BDOS modules can be selected using DRI-CPM3.SUB or USE-ZPM3.SUB prior to building everything with BUILDALL.SUB.
You'll need Hector Peraza's ZSM4 Z80/Z180/Z280 Macro-Assembler V4.0 beta 9 or later as well as CP/M-Plus supplied LINK and GENCPM utilities too.
ZSM4 is available from the RetroBrew Computers Forum at https://www.retrobrewcomputers.org/forum/index.php?t=msg&th=93&goto=3700&#msg_3700
The BUILDALL.SUB build procedure produces a CPM3NBNK.SYS and CPM3BANK.SYS system image that can be copied to the boot drive user area 0 as TEST.SYS and loaded via a special version of the CP/M Loader - TEST.COM
- Known problem with Banked version. I've left my debugging enabled, so there is superfluous output for BIOS kernel routines, and a simple debugger is invoked prior to starting CP/M's console command processor. This allows memory and register examination as well as memory management manipulation. The system seems to start fine, and you can navigate different drives and run programs. If I try to use PIP to copy large files from one of the CompactFlash drives (A: thru D:) to the RAM disk (drive M:) I get verification errors and from then on there appears to be a memory corruption.
I suspect some issue with allocation of buffers (which I'll continue to look at) - however, if you see an obvious error, please raise it as a GitHub issue.
Only an updated Non-Banked CBIOS3 and a CP/M utility to support the on-board clock calendar timekeeping chip (TIME.MAC) have been added. The new CBIOS3 adds support for the DS1302 timekeeper to Non-Banked CP/M-Plus as well as character I/O changes for DEVICE support and a fix to the RAM disk size (Z280RC only has 2Mb memory)
I've also uploaded a zip file containing updated versions of CP/M-Plus binaries that have been patched for Y2K and other updates.
I am working on a CP/M-Plus Banked Memory BIOS for the Z280RC and this will be added soon.