USB Keyboard Adapter for the QL

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Silvester
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Re: USB Keyboard Adapter for the QL

Post by Silvester »

XorA wrote:
Silvester wrote: Indeed, but it is at least reliable. I always thought QL IPC serial was dodgy, but I've yet to get a USB serial adaptor to work on a laptop above 9600 reliably (CH340 or PL2303).
..ooOO :shock:

I have about a billion of those things due to my job, never had a problem with them.
Works OK at 5V TTL levels over short distance, but fails when through 1488/1489 RS232 level shifters at 38400 over a couple of metres.


David
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XorA
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Re: USB Keyboard Adapter for the QL

Post by XorA »

Works OK at 5V TTL levels over short distance, but fails when through 1488/1489 RS232 level shifters at 38400 over a couple of metres.
Thats because you need rs-485 at those distances.


Silvester
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Re: USB Keyboard Adapter for the QL

Post by Silvester »

XorA wrote:
Works OK at 5V TTL levels over short distance, but fails when through 1488/1489 RS232 level shifters at 38400 over a couple of metres.
Thats because you need rs-485 at those distances.
Using QXL or Q40 with 16650 UART RS232 levels at 38400 to MIDI works OK. Also using QPC1/2 emulators on PC with 16650 works.

Just cannot get a USB serial adaptor to work at those speeds, even just trying Minicom on Lubuntu fails.

I also have a Yamaha CBX-T3 which can convert 38400 to MIDI 31250. It has RS485 interface which will also works as RS232, though even trying a RS485 link failed.

I did notice the laptop PSU (switched mode) does cause a lot of noise on USB ground. But problem still occurs when running off battery.

Pity, I wrote a voice editor/filer for Yamaha SY35 using EasyPtr which would have been nice to use on laptop with emulator.

(The less said about the CH345 USB MIDI interface the better :x It can't do SYSX dumps!)


David
Silvester
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Re: USB Keyboard Adapter for the QL

Post by Silvester »

XorA wrote:
Silvester wrote: Indeed, but it is at least reliable. I always thought QL IPC serial was dodgy, but I've yet to get a USB serial adaptor to work on a laptop above 9600 reliably (CH340 or PL2303).
..ooOO :shock:

I have about a billion of those things due to my job, never had a problem with them.
Solution was to use tiny MAX3232 powered from same USB port (attempts with external MC1488/1489 circuit failed):

http://www.ebay.co.uk/itm/5PCS-Mini-RS2 ... SwdzVXiFJm


David
handyandy69
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Re: USB Keyboard Adapter for the QL

Post by handyandy69 »

Is there a UK version of this board yet. Would be willing to test/help convert if needed.

Cheers,

Andy.


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