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FPGA HP85B

A new project : recreating an HP85 with an FPGA (Spartan 3E) Nexys2 board
First boot with video : 27/04/2010



But some more debug needed to avoid THIS



And MUCH more to correct this one

Ok, the CPU is now correct. For the RAM it seems impossible because the Micron RAM on the board isn't cleared when the fpga start !!

Some technical informations :
The structure of the project on Xise tool.
The structure of the CPU.

Some bad news ... the behavior is somewhat erratic ... sometimes I need to reload the bit file on the fpga until the cpu(CPU) start to read the ROM correctly ... the timing with the Strataflash need perhaps some work. But on the simulation tool there is no problem ???

Some progress after a complete rewrite in Verilog (easier to debug). Now the behavior is robust. The PS2 keyboard works a little :

Some nice progress, no more self test error, no more spurious bugs on interrupt, the keyboard and the timers works nicelly :
Now it's time to look at HP85B roms and memory controler to enable electronic disks before HPIB (with IO processors and SD memory) and HP86B emulation :)
Last news, extended memory controller is ok, the HP85B roms too
Some bugs in graphic mode to hunt before trying HPIB IO

On the 8/8/2010, HPIB is now ok, time to go to the next step ... FPGA HP86B
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