Fastest rs232 port on Atari 8-bit ?

[TXG/MNX]

Hello,

 

I was looking around I to see if there are newer rs232c ports build with higher speeds then we did know for several years.

 

I know 19.200 interfaces exists and that for the blackbox a hardware patch and driver for 38.400 exists most of these interfaces are bases on 6551 acia.

 

Did anyone every build a faster one with uarts that contain a FIFO and would it be possible to have higher rs232 on the 8-bit ?

[russg]

Hello,

 

I was looking around I to see if there are newer rs232c ports build with higher speeds then we did know for several years.

 

I know 19.200 interfaces exists and that for the blackbox a hardware patch and driver for 38.400 exists most of these interfaces are bases on 6551 acia.

 

Did anyone every build a faster one with uarts that contain a FIFO and would it be possible to have higher rs232 on the 8-bit ?

The fastest I ever got was 21,000 baud using hyperspeed handler and a MIO using a 56K Hayes modem over the phone line. There's a theoretical 115,000 rs232 rate, don't think it goes any higher.

I don't know of a modem that does 115,000, the highest I've seen is a 56k modem. If you're doing a null modem computer to computer, you might get 115,000.

Oh, yes. I was using ICET, 2.76 I think.

Edited September 2, 2014 by russg

[Mathy]

Hello Rene

 

I know ... that for the blackbox a hardware patch ... for 38.400 exists ...

 

 

Hardware patch? Tell me more!

 

Sincerely

 

Mathy

[TXG/MNX]

I need to dig into this you could change the crystal on the bb i think Erhard Putz made the mod.

Bob puff wrote a driver... Its pretty old news i never modded my blackboxes but want to mod atleast 1

[BillC]

The fastest I ever got was 21,000 baud using hyperspeed handler and a MIO using a 56K Hayes modem over the phone line. There's a theoretical 115,000 rs232 rate, don't think it goes any higher.

I don't know of a modem that does 115,000, the highest I've seen is a 56k modem. If you're doing a null modem computer to computer, you might get 115,000.

Oh, yes. I was using ICET, 2.76 I think.

Modems also have hardware compression that's about 2:1, so a 56K modem can receive at about 112K baud when compression is in use. I know that when I did dialup to Compuserve I had to restrict my 14.4k modem to 9,600, otherwise I would lose data even with my MIO serial port set at 19,200.

[bfollett]

I'm pretty sure the company I worked for in the mid/late 90's had an rs232 board that could handle 460k. Not sure what device they had needed that kind of speed, but I definitely saw the boards.

 

Bob

There's a theoretical 115,000 rs232 rate, don't think it goes any higher.

 

[ricortes]

IMHO: The bang for your buck is not good for RS232 at the moment and for the foreseeable future.

 

The problem isn't just the speed, it's the utility. Even if you tossed data at a Mbps at an Atari, it would be hard to do something useful with that data in real time because of the limits of a 1.79 MHz 6502. Just tossing numbers to illustrate the point, if you had a Mbps with a 100k hardware FIFO buffer, it would fill in a second and then take the Atari ~5 seconds to empty. By useful I mean something like toss that data to a screen or fill expanded memory on a 130XE or better. It would make the initial load fast for programs that used the data for when the Atari acts on it.

 

There's also problems with cost of course. I assume you are talking about something like 16550 or better? Figure the chip, decode logic, and level shifting will eat you up in PC board space. Cost of chips plus board/connectors would probably run the break even cost to $40+.

 

The limit on using SIO2PC type interfaces is 115 Kbps and it doesn't exactly seem to be overused.

 

It would be a good hack for hacking sake. I'm not to sure how many people would need it since there are a lot of alternatives for fast parallel I/O available now and a dwindling supply of things like RS232 modems and printers.

[BillC]

I'm pretty sure the company I worked for in the mid/late 90's had an rs232 board that could handle 460k. Not sure what device they had needed that kind of speed, but I definitely saw the boards.

 

Bob

I have an old Byterunner ISA serial port card with 16650 UARTS capable of this speed. Byterunner even made cards capable of 921,400(16750/16950 UART).

[TXG/MNX]

Would love to see a fast uart with fifo on 8-bit maybe a cartridge or pbi i would pay $100.00 for the project to start

[ricortes]

Would love to see a fast uart with fifo on 8-bit maybe a cartridge or pbi i would pay $100.00 for the project to start

 

PBI me thinks. I don't think the cartridge port has the ability to interrupt the processor. I wire wrapped one years ago and had to constantly poll it to check for data. Never got the speed satisfactory. Kind of a point of diminishing returns in that the less time you spend polling the bigger the chance you will miss something. The more time you spend polling, the less time you have to do anything else.

[Mathy]

Hello Rene

 

I need to dig into this you could change the crystal on the bb i think Erhard Putz made the mod.
Bob puff wrote a driver... Its pretty old news i never modded my blackboxes but want to mod atleast 1

 

I hope you're right, but as far as I know, the mod never turned into reality. Not even into a schematic. The drivers can be found on my BlackBox page. (Look for "1. An RS232 (modem) interface")

 

Sincerely

 

Mathy

[+David_P]

Would love to see a fast uart with fifo on 8-bit maybe a cartridge or pbi i would pay $100.00 for the project to start

 

Cart is problematic, unless there's a pass-through and a jumper to select addresses. I've already got a USB Cart and an Ethernet Cart that can't be stacked, and can't be run with a modern version of SDX unless it's built-in to the computer.

 

I'm starting to lust after a 1090 type device that will let me hang multiple devices off the PBI, all at once, and leave the cartridge port free. (Of course, the 130xe and other computers with ECI will need an ECI to PBI adapter with a couple of cart ports, but I'm OK with that).

[TXG/MNX]

Hello Rene

 

 

I hope you're right, but as far as I know, the mod never turned into reality. Not even into a schematic. The drivers can be found on my BlackBox page. (Look for "1. An RS232 (modem) interface")

 

Sincerely

 

Mathy

 

Hi,

 

I will look at it, just need to make extra space on my desk to build a blackbox and other stuff, now it looks more then when a bomb exploded overhere :-)