Hello,
During past days, I made some progress.
The MMC card is attached to the ATMega microcontroller, low level routines are working.
After reading the answers to my last question (To FAT or not to FAT), I decided to FAT.
The mass storage will accept the MMC cards with FAT filesystem.
In the first version, it will accept the first file in the directory, which will contain the LIF file system. This file can be either 128KB long or 640KB long. With this file, the unit will mimic the HP-IL mass storage.
Currently, the whole system is able to scan files in the root directory, check them if they contain the LIF file system and "mount" the file system.
I suppose that during the weekend, I will implement the LIF file system parsing, reading of files and sending them via HP-IL.
After that, the mass storage should be able to react normally to comands like "DIR" or various read commands.
After that, I will concentrate to management of caching and I will try to implement the write (better to say, read-erase-write) functions.
In the last stage (during Dec2003 or Jan2004) I will rewrite the IL routines and the unit will simulate several HP-IL peripherals. Something like 5 disk units and 3 tape units. I will see, how much RAM memory I will have available for various buffers and structures.
After that, I will concentrate on the hardware design (PCB, batteries etc.), I will make some PCBs and I will need couple of beta testers :-)