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MEGA65 / open-roms

A project to create unencumbered open-source ROMs for use on selected retro computers
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incorporate 2400 baud routines by George Hug into custom rom #26

Open rob-lindman opened 5 years ago

rob-lindman commented 5 years ago

In Transactor Magazine, there was an article by a fellow named George Hug, which went into depth about the deficiencies of the Commodore 64's handling of the user port. This has become somewhat of a standardized library for my favorite software, terminal programs. Lately, there are a number of custom roms popping up, and I am curious if anyone out there has made effort to modify the default C64 roms so they would be able to handle 2400 baud+ without loading this routine? Maybe you are bored and would like the adventure. -- I was directed here by Paul Gardner-Stephen on Facebook.

gardners commented 5 years ago

Hello,

If you can point us to the actual code for this, it will help us to implement it.

Paul.

On Mon, 8 Jul 2019 at 02:42, Rob Lindman notifications@github.com wrote:

In Transactor Magazine, there was an article by a fellow named George Hug, which went into depth about the deficiencies of the Commodore 64's handling of the user port. This has become somewhat of a standardized library for my favorite software, terminal programs. Lately, there are a number of custom roms popping up, and I am curious if anyone out there has made effort to modify the default C64 roms so they would be able to handle 2400 baud+ without loading this routine? Maybe you are bored and would like the adventure. -- I was directed here by Paul Gardner-Stephen on Facebook.

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rob-lindman commented 5 years ago

https://archive.org/details/transactor-magazines-v9-i03/page/n63

gardners commented 5 years ago

Thanks, Paul.

FeralChild64 commented 5 years ago

Someone recently did some updates to the code - https://github.com/nanoflite/c64-up2400-cc65

FeralChild64 commented 4 years ago

As I'm in the process of refactoring the Kernal I/O stack, I'm going to try to integrate both UP2400 (by George Hug) and UP9600 (by Daniel Dallman) - they will be selectable at compile time.

gardners commented 4 years ago

Hello,

Super!

Paul.

On Wed, 30 Oct 2019 at 03:17, FeralChild64 notifications@github.com wrote:

As I'm in the process of refactoring the Kernal I/O stack, I'm going to try to integrate both UP2400 (by George Hug) and UP9600 (by Daniel Dallman)

  • they will be selectable at compile time.

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ssuukk commented 4 years ago

Note though, that up2400 code contains a "fix" for receiving 0, which is not how rs232 is supposed to work (NUL should be escaped), as stated in discussion on author's page:

https://modelrail.otenko.com/electronics/commodore-64-fixing-rs-232-serial-limitations

Quote:

It seems that the c64 is almost binary transparent via rs232. The thing is; $00- $1f are control characters- very useful things to have. So we set up for transmission: $1b is the escape control code. if we want to send any binary number between $00- $1f we first preface it with the escape code $1b then the binary number EOR $20 is sent. On reception if we receive $1b we throw it away, get the next character and EOR it by $20 and that’s binary transparency. The cool thing is that all the other control codes when sent in the clear can be used to communicate out of band and control the receiver- the sky is the limit.

FeralChild64 commented 4 years ago

I have seen the comment about 0 in UP2400 source code, but I didn't know the reason. OK, thank you for the information.

Sadly, I haven't integrated UP2400 yet, I'm constantly busy with other features.