CartFlasher

Apart from the 256K RAM expansion cartridge there is also 256K flash expansion cartridge for the F256 K/Jr. available from Foenix Retro Systems. This cartridge contains extra flash memory which can be used to store software and data in a non volatile fashion. The extra memory is visible at 24 bit address $100000. The MMU (see Memory Management) can map the 32 8K blocks on the cartridge as blocks $80 to $9F into the 64K base memory.

When booting your Foenix the MicroKernel looks for a Kernel User Program (see File Formats) to start in the flash cartridge, in the on-board flash memory and (depending on the position of your DIP switches) also in the on-board RAM. In a typical system configuration on a system with a flash expansion cartridge the first memory region to be searched is the memory occupied by the flash expansion cartridge. Or in other words if there is a KUP in your flash cartridge the first one found will be started automatically after power on and after each reset. If you want to write data on your flash expansion cartridge then there are two programs which can be used for this purpose

• F256_FlashCart: https://github.com/Red-Fool/F256_FlashCart
• fcart https://github.com/rmsk2/cartflash

Both do run on your Foenix machine. F256_FlashCart always erases the whole flash chip before writing new data to it. fcart allows to incrementally write data to a flash cartridge by only erasing the flash blocks which it is told to overwrite.

The 256K flash chip is a SST39LF/VF020 by Microchip. Its data sheet can be found here. The data sheet is necessary if one wants to understand what both of the programs linked above actually do. The flash cartridge is also compatible with the K2/JrJr.