Expanding TRS-80 Level II BASIC

[daverand]

BASIC can already make full use of upper and lowercase in any string. But to display that on the screen requires the additional bit in video memory... I guess I'm not sure what "make full use of it" means?

 

[GK2001]

I guess I'm not sure what "make full use of it" means?

Quoting my first post on this topic - printing to "video memory":

"For example, if you type LPRINT "Hello" (holding down shift while typing "ello"), "Hello" will go to the printer even so "HELLO" gets printed to the screen, regardless if you have the lowercase hardware modification or not."

 

[daverand]

You can already do this - no problem. No changes required.

But without that additional bit installed, writing 0x61 to video memory will result in 0x41 being read back from video memory.

 

[GK2001]

But without that additional bit installed, writing 0x61 to video memory will result in 0x41 being read back from video memory.

Why on earth do you keep banging on about this additional bit? I am specifically talking about systems equipped with the lowercase hardware modification. I don't think that my first post on this topic was ambiguous about this fact.

You can already do this - no problem. No changes required.

Pray tell. How can I get the BASIC interpreter to display lowercase text?

 

[krebizfan]

According to http://www.trs-80.org/radio-shack-lower-case-kit/ there was a lower case driver for Level II BASIC.

 

[daverand]

Apologies - I missed that, among all the bit-banging. Sorry about that.

I know I did this back in the 80's so was confused about the confusion. So I just tried, and to my shock, it does not work. And then I remembered, there was a driver that I used (and ended up co-opting and adding to my standard codebase of assembly). @krebizfan is exactly correct. Add the driver, and all will be well.

TRS-80 Manual: Upper and Lower Case Driver Programs (19xx)(Tandy) : Free Download, Borrow, and Streaming : Internet Archive

TRS-80 Manual: Upper and Lower Case Driver Programs (19xx)(Tandy)

archive.org

And here's a copy of the mod with the program included in hex.

 

[GK2001]

OK, sweet. Currently searching for *.CAS file of the driver.

 

[GK2001]

And here's a copy of the mod with the program included in hex.

Keying this into TBUG shortly....

 

[Eudimorphodon]

FWIW, it's my recollection that with the standard lowercase driver you still had to be careful to type BASIC keywords in uppercase. I believe some DOSes patched this so commands could be entered in lowercase, but it's been a while.