Char and line delay on Serial port

[Robb Bates]

Wayne, what would it take to include a configurable character and line delay on any character output device?  Unless CP/M already has that feature built in...

Using my cassette interface, I'd like to be able to LIST a BASIC program with the line delays during the output so that I can load the data back off the cassette and have the line delays included so BASIC has enough time to process the line just entered.

Robb

[Wayne Warthen]

Hi Robb,

If I followed your prior posts on the cassette interface correctly, you are attaching to the RC2014 via a serial TTL connection.  What type of serial interface on the RC2014 is being used?  I would expect the serial port buffer to be sufficient to handle the end-of-line issue without any arbitrary delay.  What baud rate is being used?

Thanks, Wayne

[Robb Bates]

Correct, The device is just a cassette audio to serial TTL converter. No bus interface to the computer itself.  It's currently just running at 300 baud, but I'm hoping to be able to crank it up to maybe 2400 or even 4800 baud.  My machine uses the SIO/2 serial interface.  No hardware buffer there as far as I know.  So any buffering would have to be done in the BIOS.

I haven't actually run into any problems with not being able to process any incoming text.  I was just thinking ahead.

I didn't think about the serial buffer.  So you believe the buffer should be able to handle the processing delay?  How big is the buffer in the BIOS?

Robb

[Robb Bates]

I just dug into the sio.asm file.  32 bytes?  With start and stop bits, that should work out to about 1 second delay.  Yeah, that should be plenty at 300 baud.  But 1200, 2400, 4800... most likely could be an issue.

Is there anything stopping someone from cranking the buffer size up?  Is there a limit?  256 perhaps...one byte?  That should give about 1 second for 2400 baud and half a second at 4800 baud.  Still plenty I think.... assuming the worst case delay is around 300 msec according to some random thing I saw online a one point.

Robb

[Wayne Warthen]

Yes, the buffer size is just an equate in sio.asm.  It definitely cannot go above 256 because it is using a single byte length.  Should be plenty.  I will be impressed if the cassette interface can hit 4800 baud.  Seems like 2400 baud was the most I have ever seen.

Thanks, Wayne