The New View a 68000 datasheet

68000 datasheet

, the CPLD used to interface the SRAM to the Amgia's system bus , and the PIC32 microcontroller used to perform IDE I/O operations and transfer data to SRAM, as well as flashing the CPLD . the CPLD program schematic compiled to VHDL , the PIC32 microcontroller program C and MIPS32 assembler , and the Amiga device driver 68000 assembler . The Amiga device driver is uploaded to SRAM early during the PIC32's startup sequence, where the Amiga operating system will find it and link it into the system device lists. The Amiga device driver is added to the system device list as "idedisk.device". The Amiga device driver and the PIC32 firmware cooperate to emulate SCSIDIRECT access, however, the implementation is currently minimal, and just implements enough commands for you to be able to use HDToolBox. The device driver also supports CDROM drives through Commodore's "cdfilesystem" cdrom file system driver. The driver also supports RigidDiskBlock and Autobooting, and requires Kickstart 1.3 or later it has been tested with 1.3, 2.0, and 3.1 Kickstarts, and on 68000 and 68030 based systems . It also supports receiving and responding to Amiga commands, I/O to and from IDE devices Flush, Rest, ReadSector, WriteSector, IdentifyDevice and Packet commands , I/O to & from SRAM. It also does the majority of the work for SCSIDirect emulation, and when the controller is idle, it polls attached CDROM drives for disk change events and passes them on to the Amiga device driver. As a side note, this controller was initially targetted to the Commodore CDTV, however it has different firmware its expansion ROM kicks the regular Kickstart 1.3 out early in the boot process which scans only areas used by the CDTV specifically, the CDTV ROM only scans $F00000 - $F3FFFF whereas the normal kickstart 1.3 would scan $F00000 - $F7FFFF . As a result, autoboot is impossible on the CDTV without implementing the Amiga's autoconfig protocol, modifying the expansion ROM to include the correct area in its powerup ROM scan, building up a device for the expansion port which uses A2091 boot emulation included in the system ROM , building up a device for the external memory card reader which is scanned by system ROMS , or disabling the expansion ROMS. PERFORMANCE : The Amiga device driver was originally written in 68000 assembler, and has been added to, but not optimized. OWNERSHIP OF SOURCE CODE : Certain portions of the source code are not mine nor do I claim ownership of them, although I believe that they are being used within the confines of their licenses with this project. 1 Code in LOADSEG.ASM in the Amiga device driver seems to be Commodore-Amiga example code tailored for boot devices, which I am using to load/link file systems off of the hard disk. 2 Code in IDEDISK.DEVICE.ASM in the Amiga device driver is based off of the Commodore-Amiga device driver example code for a ramdisk. Most of the code was thrown out, as I only used the portions applicable to this application ROMTAG, task initialization, and IOREQUEST parsing are pretty much the only things that remain, the rest needed to be rewritten to talk to my hardware . HARDWARE DEVELOPMENT ENVIRONMENT : The first "kind of working" prototype was a proof-of-concept assembled with the PIC32MX starter kit, the PIC32MX I/O expansion board, and two PICTAIL prototype boards, one with the IDE interface/UART level shifter, and the other with the SRAM IC. Two versions of the device driver, one for ROM use compiled at $00F42000, and another for use as a disk-based driver, are compilable from the sources. When it came time to downcode to assembler, signal rise and fall times on the prototype board were measured with the DSO, then considered along with data sheet times, and the assembler instructions/cycles were manually counted timing comments are still in the assembly source code to make sure no access times were violated. TERMS OF USAGE : The Source code provided on the web page is hereby released for Public Domain unrestricted usage, except those sections noted in the OWNERSHIP OF SOURCE CODE section. You must comply with the licenses attached to those sections of code, especially the Xilinx code as it is probably outside the scope of its license to use the JTAG code to program non-Xilinx parts.
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