RS232 - A fork in the road

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jrubin
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RS232 - A fork in the road

Post by jrubin » Sat Jul 05, 2014 4:00 am

The program I'm currently putting together requires communication with a radio VIA RS232. Its purpose is long winded though if you are interested
you can have a look at CPAN [url]https://metacpan.org/pod/Ham::Device::FT817COMM/[url]

I have written the PERL module which communicates with the radio and released it to the public

The C64 has no RS232 port, and Im wondering which way to go with this

1: Most widely used add on RS232 solution for the C64
2: Something in software to allow the existing port to function as RS232

If I write a program that has no way of connecting to the rig, or a solution that only a handful of folks have. It won't serve any great purpose.

Please share any recommendations on how to proceed with this. I imagine the most popular method will probably be supported within vice to make writing the code easier to test

The RIG can communicate at 4800 or 9600 or 38400


Communication works as follows, The format is 8 data bits, no parity, 1 start bit, and 2 stop bits
READ
[Address MSB] [Address LSB] 00 00 BB

WRITE
[Address MSB] [Address LSB] [DATA] [DATA(ADDRESS+1)] [BC]


Ill get more into the inner workings on another thread, for now the issue is the interface

thanks

Jordan



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Re: RS232 - A fork in the road

Post by dudz » Sat Jul 05, 2014 10:48 am

2: Something in software to allow the existing port to function as RS232
such software already exists in the kernal - the user port is used as rs232 port then. if you can live with TTL levels instead of proper rs232 voltages, you can directly interface to the user port.

that said, max. speed then is 2400baud - to go faster you will need one of the interfaces that has an UART on them

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Re: RS232 - A fork in the road

Post by jrubin » Sat Jul 05, 2014 5:04 pm

Yeah, minimum is 4800 so a bolt on port will be required.


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Re: RS232 - A fork in the road

Post by dudz » Sat Jul 05, 2014 6:58 pm

you could try using the CIAs serial shift registers ... the "UP9600" driver in novaterm uses that, for example - with that you can do 4800 baud fine (and much more if half duplex is ok)

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Re: RS232 - A fork in the road

Post by jrubin » Sat Jul 05, 2014 8:45 pm

Its all half duplex. Any good source on documentation to accomplish this

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Re: RS232 - A fork in the road

Post by dudz » Sat Jul 05, 2014 10:52 pm

google "daniel dallmann 9600 baud" or something like that.... novaterm 9.6 has a driver for it as well, which should fairly be easily disassembled. or you just look at the CIA datasheet, the idea is simply to use the CIAs shiftregisters instead of doing bitbanging in software.

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Re: RS232 - A fork in the road

Post by jrubin » Sat Jul 05, 2014 11:15 pm

Searching returns hardware, is this a hardware device to be constructed or within software

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Re: RS232 - A fork in the road

Post by jrubin » Sat Jul 05, 2014 11:58 pm

I found this. I imagine it should be integrated or loaded along with the existing software being written


http://www.jamtronix.com/files/novaterm ... up9600.txt

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Re: RS232 - A fork in the road

Post by dudz » Sun Jul 06, 2014 11:20 am

the hardware part is only needed if you need actual rs232 levels (it describes how to modify an existing rs232 interface)... again if TTL levels are ok, just wire up directly to the port.

the code is the one i was referring to... there should also be a small self contained (and very dumb) terminal program somewhere that supports this (also written by daniel i believe)

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Re: RS232 - A fork in the road

Post by jrubin » Sun Jul 06, 2014 8:40 pm

Lets assume for a moment that the rig would respond well from the 5v from ttl. how would the commodore user port respond from the 12v from the rs232?

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