As promised in a previous post I’ll go into more detail of the various mods I installed in my Commodore SX64. Today I describe the ‘SX64 Commander’. It basicly controls all other mods inside the Commodore and provides visible feedback with 7 segment display of its state. A couple of button will provide quick access to common functions.
The top two 7 segments displays shows the current Kernal and appropriate DOS ROM (i.e. with a DolphinDos Kernal, the internal 1541 have extra RAM and Dolphin DOS ROM switched in). Since it has more then 30 Kernals, there is a button that switches quickly to the stock SX Kernal and another one resets the system. The next two 7 segments displays shows the ID of the internal drive. The internal SD2IEC wil have ID 9 when the internal drive is 8 and vice versa.
To switch between Kernals and drive ID’s the RESTORE key is used. A long press (>2s) cycles through the Kernals, where a short press (plm. 1s) followed by a long press will cycle through internal drive ID 8 and 9.
The package consists of a button/LED board and the real controlboard. This provides:
- SPI interface to the RAM/ROM board in the 1541.
- A13-A18 to select up to 64 Kernals.
- Misc. C64 signals (!RST, !EXROM) to provide an unstoppable reset.
- Displayboard interface (on the bottom)
The display board is a copy of the reference schematic of the TM1651, which I salvaged from an old Go-tek. Two LEDs and buttons are added to break out the SD2IEC controls.
