This page contains the details of a project being undertaken by David Fry and me to build a modern version of the Microtan 65 system. Many of the items developed are available for purchase at the shop here. A suitable starter project is described here.
The PCBs are being developed using KiCad (kicad-pcb.org). The KiCad project files have been archived in the ZIP files in the relevant sections below and include the Gerber files for PCB production.  Index
|Serial Keyboard Interface|
This is a modern replacement for Tangerine's latest version CPU card. It is fully compatible with the original and has the following enhancements:
Bare MT65-R CPU v1.0b PCBs are available for sale in the Shop
Note: The FORTH programs require Rev2 code for its 'Words' to be displayed correctly. This is because the 6502 code stores Words with the 8th bit of the last character set to denote the end of the word.
Note: TUGBUG cannot be used with a MT65-R CPU board in Single Board configuration (ie with the 3 links closed and no TANEX). Explanation here
This is a modern replacement for Tangerine's Tanex card. It is fully compatible with the original and has the following specification:
Note: UART 6551 may be substituted with 65C51 in PCB versions 1.0b and above.
Bare Tanex-Plus v1.0b PCBs and programmed memory are available for sale in the Shop
A modern 64K RAM board produced by Barry Graham and is based on the TUG 64K RAM board. Note: This board is for use with the original TANEX. It cannot be used alongside the TANEX-PLUS as both board address the same memory range.
Full details are available on Barry's web-page.Manual
Modern replacement for the Tangerine TANDOS 65 board.Manual
EPROM U17 is a 2732 EPROM containing both the TANDOS and DBASIC images.TANDOS Listing
This is a modern replacement for the Tangerine High Resolution Graphics (HRG) board.
Provides 256x256 pixel high resolution graphics screen. When used with the HRG Toolkit can also provides a 51 character x 45 line high-resolution text screen. Modulated UHF and composite video outputs available.Manual
Bare HRG v1.0b PCBs and programmed Toolkit EPROMs are available for sale in the Shop
This is modern replacement for the Bulldog Soundcard. It includes a battery backed Real Time Clock module. The PCB design, Manual and supporting software were developed by James Price. It has the following specification:
Supporting SoftwareSNDEMO.txt - Sound demo program in BASIC
Because of the size of the associated .wav files, they are held on my FTP server. If you wish to download any of these files, please send me an email (address is on the Home page) and I will provide access information. All .wav files have been saved at 'FAST' speed.
James has also been experimenting using the soundcard as a musical instrument. He has generated a document that captures the various steps he has taken.
The associated software files are also available on my FTP server.
This EPROM Programmer is capable of reading and programming 2716 and 2732 EPROMS. It connects to TANEX parallel port sockets A,C and D and requires an external power supply to provide the Vpp programming voltage.Manual
Replacement for Tangerine Keyboard (MT020)
The circuit is identical to MT020 Issue 3 except the mechanical Caps-Lock switch is replaced by a software toggle function.KiCad Archive (zip file)
Photo of Keyboard in its case.
Replacement for Tangerine KeypadKiCad Archive (zip file)
What started life as a bespoke 19 inch 4U system rack has been modified to accommodate the Microtan Circuit Boards and fit into my existing Vero 19 inch enclosure. This involved removing the end plates, cutting them down to size and re-drilling the holes for the screws that hold the 6 longitudinal rails in place.
The motherboard has been designed to accommodate CPU, TANEX and 5 expansion slots. The slots are 1 inch apart to allow for a wider PCB form factor and increased cooling. Tanbus expansion slot signal lines 19b and 20b have been earmarked for Video1 and Video2 signal. Each may be configured by on-board jumpers to link to Tanbus CPU slot signal lines 19a or 20a.
This motherboard has now been replaced with a prototype for the full-sized Backplane-R described below.KiCad Archive (zip file)
The Backplane-R is a direct replacement for the Tangerine MT0010 Backplane. It accommodates CPU, TANEX and 9 expansion slots. Again the slots are 1 inch apart and expansion slot signal lines 19a and 20b earmarked for Video1 and Video2 signals as described above.
The onboard circuitry provides buffering for the O1, O2, CLK, SYNC signals from the CPU. Additionally Memory Page management for the memory range $2000-$BBFF is possible utilising the Block Enable signal. A full description is available here. However, this can only be used when an original TANEX is fitted. If a TANEX-PLUS is fitted with its $2000-$BBFF memory permanantly enabled, then this range cannot be overlaid by other boards.Photo (rear)
Power is supplied to the motherboard by a 65W Meanwell 1496-RQ-65B Quad Output enclosed power supply providing dual 12 volt and 5 volt supplies.
Construction notes for creating a Serial Keyboard interface to the Microtan 65 supplied by Danny Page. This interface enables a PC-AT keyboard to used with the Microtan system.Circuit Diagram
Plugs into any TANBUS slot on the motherboard. Microtan board under test plugged into the extended socket. Allows work to be undertaken on a Microtan board under test outside the system rack. Test points available for all TANBUS signal lines.