Tektronix 4051/4052/4054 GPIB IEEE-488 Flash Drive

[Monty McGraw]

I saw the recent posts on IEEE-488 on the PDP-11, and Christian's post on
his Commodore GPIB floppy drive connection to the Tektronix 4051.

I have been working for a couple of years on a GPIB/IEEE-488 Flash Drive
for the Tektronix 4051, 4052 and 4054 computers, and am getting close to
completion.

My Tektronix 4050 GPIB Flash Drive emulates the Tektronix 4924 Tape Drive,
which is supported by all the 4050 computers using secondary GPIB addresses
for commands.  This allows the flash drive to be used without needing an
option ROM Pack.  In particular, 4051 ROM Packs are not compatible with the
4052/4054 ROM Packs as the 4051 used a Motorola 6800 CPU and the 4052/4054
used a Tektronix custom 16-bit bit-slice CPU in order to improve
performance 10x and double the memory capacity from 32KB to 64KB.

The 4050 GPIB Flash Drive design uses an Arduino directly connected to my
custom interface PCB with the GPIB connector, and a micro SD Flash board.
I picked the 644-Narrow Arduino board by Pandauino as it has the Atmega644
processor which has twice the flash and RAM as the Arduino Nano and also
has 5V I/O which can interface without buffers to the Tektronix 4050 GPIB
port.  The current code takes 40912 bytes of flash and 2798 bytes of RAM
(more than the Nano) and supports PRINT, INPUT, READ, WRITE, OLD, SAVE,
BOLD, and BSAVE. These commands have been tested on my 4052 and 4054A and
my software development partner's 4051 computer.

The flash drive also adds two secondary address commands not supported by
the 4924: HEADER and CD.  We are using the Arduino FAT32 library which
supports long filenames, and create the filename to match the Tektronix
tape file header format which includes a file number, file type (ASCII,
BINARY, NEW or LAST), data type (PROGRAM or DATA) and the file size.  We
also take advantage of the extra spaces in that format to insert the file
name as a comment - like the Tektronix 4050 BASIC program to add comments
to the file header.  The CD command is for changing the directory in the
microSD card, and allows multiple different Tektronix 4050 DC300 tapes that
I have recovered and posted on my github repository:
https://github.com/mmcgraw74/Tektronix-4051-4052-4054-Program-Files to be
stored in separate directories - while maintaining the original tape file
numbers.

More info and photos in my project thread on vcfed.org:
https://www.vcfed.org/forum/forum/genres/other/64990-tektronix-405x-gpib-flash-drive

Monty McGraw