BBC Micro and Electron

[anightin]

Hi There,

I have been using a Computer Concepts PRINTMASTER ROM (for EPSON printers) in my BBC Master and Electron

CTRL<B> Printing for listings etc seems to work fine.

However, when using the *GDUMP to dump the screen, it seems that the graphics data is printed in contiguous 'strips' vs a linefeed between each.

I have set the config/auto_linefeed to Yes but that doesn't seem to help.

I've attached eps and raw along with the top line of the output if that helps

PDF_Output.png (10.05 KiB) Viewed 7469 times

EPS_RAW.zip

(2.13 KiB) Downloaded 449 times

I noted the following in the PRINTMASTER manual:

Screenshot 2020-12-01 at 22.25.18.png (38.24 KiB) Viewed 7466 times

I am wondering if the auto_linefeed option is working as intended?

[RWAP]

At a quick glance (without breaking down the EPS file), this is a graphics printout. My guess is that you need to increase the timeout setting as the BBC is probably quite slow at sending the graphics data - if that is the issue, you should have two or more files generated each time you try to print the data.

The automatic linefeed only affects printing of text

[anightin]

Hi There,

I tried adjusting timeout and delay but no change in output.

I then tried the *FX 6,0 and the printout appeared as expected.

Screenshot 2020-12-02 at 11.38.44.png (92.39 KiB) Viewed 7460 times

From the Electron manual:

FX6.png (38.06 KiB) Viewed 7460 times

So I can issue the FX command to resolve for now, but Is there any other way I can tell the RetroPrinter that it should add a LF when a CR is sent if not the /root/config/auto_linefeed (Yes)? -- as there is no EPSON DIP switch to set permanently

[RWAP]

That is really odd. If it was the auto_linefeed setting, you would have expected the graphics to all print on top of each other, as the carriage would return to the left hand side but no line feed. As it was, your graphics were not corrupted it was more that they finished printing prematurely.

Actually, the description you included from the Electron manual makes no sense! If *FX6 means "ignore single character" surely *FX6,0 means ignore the NULL characters - don't print them.

Looking at the original EPS file, this was full of null characters between the various graphics commands. Why they are there is anyone's guess, but that would explain why the *FX6,0 works as it prevented the hundreds (if not thousands) of null characters. Whilst the conversion routine does nothing with a null character (outside of a graphics dump), it is possible that there is an error in the code to check whether the timeout has been reached before characters are received from the centronics connector, so I will need to investigate that.

As I said, increasing the timeout would probably have resolved the issue.

I guess the Electron manual has an error and is meant to say *FX6,10 (ie do not send line feed characters if the printer has auto line feed enabled) - that is certainly what the BBC Micro User manual says - https://central.kaserver5.org/Kasoft/Ty ... /Ch42.html

[RWAP]

Just re-read that extract from the Electron manual - I think what it means is that by default it uses *FX6,10

Entering *FX6,0 enables line feed and disables the null character instead (which may be the default on the BBC)

So the auto line feed is a bit of a red herring here. I need to investigate whether 100+ null characters sent to the GPIO pins are actually seen as 100 characters, or allow the timeout to trigger.

[anightin]

Just re-read that extract from the Electron manual - I think what it means is that by default it uses *FX6,10

Entering *FX6,0 enables line feed and disables the null character instead (which may be the default on the BBC)

So the auto line feed is a bit of a red herring here. I need to investigate whether 100+ null characters sent to the GPIO pins are actually seen as 100 characters, or allow the timeout to trigger.

Thanks for looking into this for me, I'd be interested to see what you find.

In terms of flow, the data light flashes continuously for 3-4 mins whilst the dump command is executing, at the point when I get the prompt back on the Micro, there is an 8 second delay as expected (timeout = 8) before the power light flashes to indicate the pi is sending data to the printer.

I enclose another couple of test cases for you using the same PRINTMASTER ROM, but this time using a *GPRINT command to get different text styles, again using graphics mode.

Page 12 is output with *FX 6,0
Page 13 is the same output with *FX 6,10

Note that I do get over-lapping print on page 13 output when linefeeds are ignored. Page 12 is output as expected.

[anightin]

Just re-read that extract from the Electron manual - I think what it means is that by default it uses *FX6,10

Entering *FX6,0 enables line feed and disables the null character instead (which may be the default on the BBC)

So the auto line feed is a bit of a red herring here. I need to investigate whether 100+ null characters sent to the GPIO pins are actually seen as 100 characters, or allow the timeout to trigger.

Thanks for looking into this for me, I'd be interested to see what you find.

In terms of flow, the data light flashes continuously for 3-4 mins whilst the dump command is executing, at the point when I get the prompt back on the Micro, there is an 8 second delay as expected (timeout = 8) before the power light flashes to indicate the pi is sending data to the printer.

I enclose another couple of test cases for you using the same PRINTMASTER ROM, but this time using a *GPRINT command to get different text styles, again using graphics mode.

Page 12 is output with *FX 6,0
Page 13 is the same output with *FX 6,10

Note that I do get over-lapping print on page 13 output when linefeeds are ignored. Page 12 is output as expected.

Just wondering if you've managed to take a look at this yet? or have an estimate for when you might be able to investigate?

Keep up the good work and Happy New Year!

[RWAP]

Can you try the v3.8 softwre image - https://www.dropbox.com/s/9buj3z15228qw ... 8.img?dl=0

Not sure if this will help with the Electron. I can't see that the 100+ NULL characters should cause an issue.

[anightin]

Can you try the v3.8 softwre image - https://www.dropbox.com/s/9buj3z15228qw ... 8.img?dl=0

Not sure if this will help with the Electron. I can't see that the 100+ NULL characters should cause an issue.

Thanks for the suggestion but the results are the same as previously reported.

Also, I did notice that in 3.8 I had to change the default Emulation from HP to Epson.

[RWAP]

Yes the v3.8 is not an official release as such.

Not sure what the Electron is doing to be honest. The only other option would be to increase the printer_delay setting to see if that helps.