Are there multiple Sharp CE-150 ROMs?
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03-04-2023, 08:15 PM
Post: #1
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Are there multiple Sharp CE-150 ROMs?
While again working on disassembling the CE-158 ROM (serial interface for PC-1500), I found a section of code that looks for the presence of the CE-150 printer/cassette interface. It does this by poking a small bit of code into RAM and calling it. This is done as the CE-158 can't directly 'see' the CE-150 address space.
It surprised me that it tests for three possible values: $00, $6D, and everything else. With nothing hooked to the expansion port you will get an $FF. With the CE-158 only you get an $F7 (this is just a nonsense value as nothing at this address in CE-158). With both the CE-158 and CE-150 (or just the CE-150) you get a $D7 which is the value at that address in the CE-150 ROM. You can't directly PEEK this address form BASIC it requires twiddling the SPU/SPV lines and disabling the interrupts. Below is a bit of code in a BASIC which will poke a machine language program into RAM, run it, and print the result out (in decimal.) If you happen to have a PC-1500 and CE-150 would you mind running this little program and posting the results? Having a CE-158 is not required. Thanks. 100:POKE &7A26,&FD,&BE,&B8,&A5,&A2,&97,&A8,&FD 110:POKE &7A2E,&81,&AE,&7A,&33,&9A,&AA 120:CALL &7A26 130:PRINT PEEK(&7A33) 140:END |
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Messages In This Thread |
Are there multiple Sharp CE-150 ROMs? - Jeff_Birt - 03-04-2023 08:15 PM
RE: Are there multiple Sharp CE-150 ROMs? - robve - 03-05-2023, 03:21 AM
RE: Are there multiple Sharp CE-150 ROMs? - Xorand - 03-06-2023, 04:47 PM
RE: Are there multiple Sharp CE-150 ROMs? - Jeff_Birt - 03-06-2023, 04:51 PM
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