6530 adapter

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Kakemoms
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6530 adapter

Postby Kakemoms » Mon Apr 17, 2017 1:37 am

I have made a new 6530 adapter that I will get in a few weeks from DirtyPCBs.

The adapter is only 2,2cm x 5,7cm and has space for a 6532, an 8KB eprom and a 74ach02. It will only work for Commodore 2040-8050 series of disk drives. The original design came from Ruud Baltissen, and I only modified the capacitors layout and eprom to make everything smaller.

6530-Adapter-3D.png


I will sell the PCBs here (if it works) for about the cost. You will need to solder it yourself.

eslapion
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Re: 6530 adapter

Postby eslapion » Mon Apr 17, 2017 11:02 am

@Kakemoms
I have seen these weird ROMs used in PET computers too.

Is there any particular reason why it would only work in disk drives ?
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Kakemoms
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Re: 6530 adapter

Postby Kakemoms » Mon Apr 17, 2017 3:09 pm

Commodore made different versions of the 6530, so apparently they have a slight difference in a mask programmed ROM that define the organization of the internal working of the registers and some of the chip pins (pin 15,16 and 17 specifically).

Now the pins wouldn't really prove any problem as we can rewire to the pins on the 6532 with jumpers, but there are a number of peculiarities in the 8050 that Baltiussen points out in his web page. One of the things is that the drive has a 6522 connected to the same CS line as the 6530, so that both chips are selected at the same time. Apparently internal circuitry in the 6530 prevents it from being selected if the accessed address is slightly different (from the address range of the 6522), which is why he had to add a 7402 to construct that logic externally.

I have no idea how the logic around/in the 6530 in other machines work, but apparently you have to know the address decoding of the machine in order to reconstruct the logic in the 6530. In the datasheet (of the 6530) one can see at least 7 different versions as examples. Both 6530-002 and 6530-003 are for the KIM-1. One 6530 was used for the Commodore Chessmate. 2040/3040/4040 drives with DOS1 has a 6530-028, while DOS2.1 (in the same drive) is a 6530-034. 6530-038 and 6530-039 were used in the 8050.

So, quite confusing! But for all drives the internal address decoding is at least the same (only eprom contents vary).

Which PET did you see a 6530 in?


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