Video Terminal Project
If you just want firmware to run on your VT board and you don't have time for the rest of this stuff ...
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The
Spare Time Gizmos' Video
Terminal project is a family of general purpose video display terminals.
They communicate with a host computer using standard RS-232 ASCII
communications and accept ANSI standard escape sequences. The VT terminals
use any standard IBM PC compatible VGA display as a monitor and an IBM PC
PS/2 style keyboard for input.
The VT family terminals are perfect for use with any computer that requires a serial console, especially those of the classic variety. It works with the Spare Time Gizmos SBC6120 and Elf 2000 kits, as well as any VAX, PDP-11, S-100, or other vintage machine that you might have. Since the VT family has near perfect emulation of the DEC VT220 terminal, it works with any vintage software that you might have, including EDT or emacs.
Features
The VT terminal can do pretty much everything a VT220 can do, plus several extensions. Here's just a partial list of the features -
- Two independent serial ports for two hosts, or host and printer*
- Multiple frame buffers with split screen and paged displays*
- A programmable 25th line status display
- Menu driven setup mode with settings saved to EEPROM.
- Reverse video, underline, dim, bold, blinking, double high and/or double width character attributes
- VT525 escape sequences are supported to set foreground and background colors
- Automatic screen saver and power down for VESA DPMI compatible monitors
- Supports standard PS/2 104 key PC keyboards
- Supports LK250, LK411, LK412 and LK450 keyboards in DEC native mode*
- Software selectable DTE or DCE configuration
- DEC Multinational, UK National, DEC Special Graphics, DEC Display Controls and VT52 fonts
- Downloadable fonts, optionally saved to EEPROM.*
- Serial printer port with VT220 printer controls*
* planned features that still need someone to implement them.
Firmware
The firmware for the VT family is an open source community development effort. The firmware is written in C and is compiled using the free SDCC compiler. The other tools we're using are Programmer's Notepad and GNU Make, both of which are also free, open source, tools. New firmware can be downloaded to VT microprocessor, while it's installed in the terminal, using an ordinary PC and a serial connection to the terminal. No special programming hardware is required to update the MCU firmware and all the development tools used are free. Lack of money or equipment shouldn't keep anybody from participating.
Hardware
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The
VT family terminals contain two independent microprocessors, a primary “MCU”
which does most of the work including generating the video, and a secondary
“APU” which interfaces to the PS/2 keyboard and handles other miscellaneous
housekeeping tasks. The video generation is done by a combination of
hardware and firmware. The hardware generates the basic horizontal timing,
and the firmware is responsible for transferring bytes from the frame buffer
to the hardware video shift register, which is then shifted out serially to
drive the VGA display.
Developers
The team responsible for bringing your the VT project includes -
-
Bob Armstrong <bob AT SpareTimeGizmos.com> - hardware, administrator
-
James Markevitch <jam AT magic.com> - the majority of the firmware
-
David Betz <dbetz AT xlisper.com> - menus, development tools
News
-
8-Apr-09 - VT6 hardware released to production
You can build your own VT from scratch, but if you want a head start you can buy PC boards and kits from the Spare Time Gizmos web page.
We need your help, and don't worry if you aren't a programmer. We need document writers, Q/A testers, and even somebody to maintain this Source Forge page!
We do our best, but nothing is perfect. If you find a problem, let us know and we'll see what we can do about it.
We especially want to thank the nice people at Source Forge for hosting this project.