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CS/A65 PETCPU Jumper settings

(C) - André Fachat

This table describes the jumper settings available on the board

Jumper Description Setting Meaning VC1581 setting PETCPU setting
JP1 1/2MHz system clock switch 1-2 2 MHz * 8032 (experimental)
2-3 1MHz 4032
JP2 I/O size selector A8 1-2 A8=0 don't care
2-3 A8 don't care *
JP3 I/O size selector A9 1-2 A9=0
2-3 A9 don't care *
JP4 I/O size selector A10 1-2 A10=0
2-3 A10 don't care *
JP5 ROM size selection. JP5,6, and 7 select the lowest address where ROM is selected (from 64k down). A15 is always high 1-2 A14 high
2-3 A14 low * *
JP6 1-2 A13 high *
2-3 A13 low *
JP7 1-2 A12 high *
2-3 A12 low *
JP8 External (bus) memory A17 1-2 +128k *
2-3 +0k *
JP9 External (bus) memory A16 1-2 +0k
2-3 +64k * *
JP14 I/O select enable 1-2 /IOSEL enabled *
2-3 /IOSEL disabled *
JP15 RAM size selection. JP15,16, and 17 select the highest address where RAM is selected (from 0k up). A15 is always low 1-2 A14 high *
2-3 A14 low *
JP16 1-2 A13 high * *
2-3 A13 low
JP17 1-2 A12 high * *
2-3 A12 low
JP18 External (bus) memory A15 invert 1-2 invert A15 on bus *
2-3 do not invert A15 *
JP19 External (bus) memory A12 invert 1-2 invert A12 on bus *
2-3 do not invert A12 *
JP20 8/32k RAM switch 1-2 8k RAM (6264)
2-3 32k RAM (62256) * *
JP21 Enable on-board RAM 1-2 disable on-board RAM (use bus memory only) depends on whether you have on-board RAM
2-3 enable on-board RAM, use bus memory only above address set with JP15/16/17. *
JP22 ROM address A18 1-2 0 depends on the ROM size and where the ROM content is in the ROM IC. For example I have a 64k ROM, and the PET ROM at $0000-$7fff, and the VC1581 ROM at $8000-$ffff. This results in these jumper settings:
JP22 JP23 JP24 JP25
PET 4032 1-2 5-6 1-2 1-2
VC1581 1-2 5-6 1-2 5-6
3-4 Control port D3
5-6 1
JP23 ROM address A17 1-2 0
3-4 Control port D2
5-6 1
JP24 ROM address A16 1-2 0
3-4 Control port D1
5-6 1
JP25 ROM address A15 1-2 0
3-4 Control port D0
5-6 1

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Last modified: 2010-06-01
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