ZaneKaminski
Well-known member
Hi everyone,
My friend and I recently made a batch of 2MB ROM SIMMs for the SE/30 and Mac II machines. We wanted a few of these ourselves as well as to sell through our little company (price will be $25 incl. domestic US shipping):
We have also finished a design for an 8MB ROM SIMM (actually it holds two separate 8MB images) using cheap 3.3V flash (price will be $35):
Before we can sell the 2MB SIMMs or try the 8MB SIMMs (or feel pleased about the project haha), I must implement our ROM disk driver, similar to what bbraun and BMoW have done. I've studied examples from IM: Devices as well as bbraun's source and have written a driver which I feel has a good structure. The driver compiles using the Retro68 toolchain and is automatically patched into a base ROM and concatenated with a disk image.
Everything seems to be in order, but my IIsi is getting stuck during boot and I am at a loss for how to debug the problem. The boot never completes but the mouse and VBL keep going. I fixed up bbraun's driver to compile with the new toolchain, and it is failing in the exact same way. I suspect a calling convention mismatch or other issue with the build and ROM patch process but I can't pin it down.
I have four logic analyzers but three are put away and the one I have been using needs its software reinstalled (big hassle) and a better SCSI upper byte terminator than my handmade one. So in terms of test equipment, I am stuck with just four-channel scopes and a 2+16ch MSO. I would rather not use that stuff anyway. I would like to print some stuff out over the serial port and see if my code is even getting called and how far it gets, but I am not sure how the boot process goes. I don't know if I can use the serial driver when the disk driver's open call and the first prime calls are made. Or is there macsbug in ROM?
We would be happy to reward those providing particularly helpful advice with some of our hardware, including the ROM SIMM and also our Apple IIe and IIgs memory expansion cards. Once we finish this project, we will be able to finish the ROMBUS for Mac Plus and 512K, which I consider to be much more interesting.
The driver is here: https://github.com/garrettsworkshop/MacIIROMDiskDriver (the ROM with our driver is in bin/rom.bin and bbraun's driver which I have recompiled is in bin/rom_braun.bin)
and the KiCAD files for the SIMM are here: https://github.com/garrettsworkshop/MacIIROMSIMM
Right now the RAM disk function and "R" key check are commented out, so the Mac should always boot from ROM.
Any help would be greatly appreciated!
My friend and I recently made a batch of 2MB ROM SIMMs for the SE/30 and Mac II machines. We wanted a few of these ourselves as well as to sell through our little company (price will be $25 incl. domestic US shipping):
We have also finished a design for an 8MB ROM SIMM (actually it holds two separate 8MB images) using cheap 3.3V flash (price will be $35):
Before we can sell the 2MB SIMMs or try the 8MB SIMMs (or feel pleased about the project haha), I must implement our ROM disk driver, similar to what bbraun and BMoW have done. I've studied examples from IM: Devices as well as bbraun's source and have written a driver which I feel has a good structure. The driver compiles using the Retro68 toolchain and is automatically patched into a base ROM and concatenated with a disk image.
Everything seems to be in order, but my IIsi is getting stuck during boot and I am at a loss for how to debug the problem. The boot never completes but the mouse and VBL keep going. I fixed up bbraun's driver to compile with the new toolchain, and it is failing in the exact same way. I suspect a calling convention mismatch or other issue with the build and ROM patch process but I can't pin it down.
I have four logic analyzers but three are put away and the one I have been using needs its software reinstalled (big hassle) and a better SCSI upper byte terminator than my handmade one. So in terms of test equipment, I am stuck with just four-channel scopes and a 2+16ch MSO. I would rather not use that stuff anyway. I would like to print some stuff out over the serial port and see if my code is even getting called and how far it gets, but I am not sure how the boot process goes. I don't know if I can use the serial driver when the disk driver's open call and the first prime calls are made. Or is there macsbug in ROM?
We would be happy to reward those providing particularly helpful advice with some of our hardware, including the ROM SIMM and also our Apple IIe and IIgs memory expansion cards. Once we finish this project, we will be able to finish the ROMBUS for Mac Plus and 512K, which I consider to be much more interesting.
The driver is here: https://github.com/garrettsworkshop/MacIIROMDiskDriver (the ROM with our driver is in bin/rom.bin and bbraun's driver which I have recompiled is in bin/rom_braun.bin)
and the KiCAD files for the SIMM are here: https://github.com/garrettsworkshop/MacIIROMSIMM
Right now the RAM disk function and "R" key check are commented out, so the Mac should always boot from ROM.
Any help would be greatly appreciated!
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