Sorcerer Tape Simulator

The Sorcerer Tape Simulator (or Tape Sim for short) is an invention by Claus B. that allows the sorcerer to load tape files from a micro SD card.  The Tape Sim uses a Teensy Arduino 3.5 to transmit a small terminal/loader program to the Sorcerer.  When the user enters the LOG command (LOad and Go) the Sorcerer runs the cod and signals the Teensy to send a menu.  This menu presents the user with a list of programs on the SD card along with a letter command to launch them.  Once a file is selected, the Sorcerer jumps to its ROM-based loader and the Teensy transmits the header and program to the system. The Tape Sim supports three different file types: BAS for BASIC files, .COM for CP/M executable files, or .BIN for MESS/MAME binary files.

The cassette tape interface on the Sorcerer can run at either 300 or 1200 baud which was pretty good for the time, but the 1200 baud speed isn't entirely reliable.  The Tape Sim allows for transmission speed of 20,833 Baud which is about the highest speed the Sorcerer could reliably handle.  While the UART can technically handle a maximum of 30,000 Baud, the Sorcerer's ROM-based loader can't keep up.  Although this speed could not be achieved back then, thanks to modern technology like the Teensy it's now possible.  This decreases the load time for a 24K program from 15 minutes (at 300 Baud) to to around 12 seconds.

Installation on the Sorcerer requires clipping or soldering wires to the motherboard.  The exact installation depends on which model Sorcerer you have.

 

Sorcerer I

Unlike the Sorcerer II, the Sorcerer I's cassette interface is on a daughterboard which feeds a UART on the motherboard.  The Teensy replaces the daughterboard and generates the UART clock signal (16 times the baud rate) using the FrequencyTimer2 library.  Teensy's second serial port connects directly to the 5V UART chip with no level converters required.  Remove cassette interface daughterboard and connect Teensy as shown:

Wiring diagram for the Sorcerer I

Sorcerer II

On the Sorcerer II, the cassette interface is on the motherboard, so the Teensy must connect directly to the UART.  To access the cassette interface, remove the power supply daughterboard then remove the UART IC from its socket at 9E.  Slightly bend up pins 17, 20, 25, and 40, just enough to clear the socket when it's plugged back in. With clip leads, connect Teensy to the UART pins then replace the daughterboard.  If it interferes with the clip leads, add a spacer under the right side bolts.

UART Teensy
1 --- +5V
3 --- Gnd
17 -- 5 FreqOut
20 -- 1 Tx1
25 -- 0 Rx1
40 -- 5 FreqOut