It is currently Sun Dec 17, 2017 8:30 am

All times are UTC - 7 hours





Post new topic Reply to topic  [ 3 posts ] 
Author Message
PostPosted: Wed Nov 22, 2017 8:38 pm 
Offline
User avatar

Joined: Sun Jan 22, 2012 12:03 pm
Posts: 5899
Location: Canada
Is it possible to detect for the presence or absence of a Family BASIC keyboard without user interaction? I don't see anything in the interface described on the Wiki that would produce a detectable signature.

I could assume it's there, by default, but I don't like that this could conflict with an expansion controller on the second D1 line. The alternative question is whether I can detect the absence of a controller on D1?

Also assuming PowerPak / Everdrive could be in the mix here, though I also assume D1 is already pulled down to 0 when not connected regardless?

The backup plan is just letting the user choose manually, but I just want to know if I'm missing something that would make it easier.


Top
 Profile  
 
PostPosted: Thu Nov 23, 2017 8:29 am 
Offline

Joined: Sun Apr 13, 2008 11:12 am
Posts: 6535
Location: Seattle
You should be able to use the "enable keyboard matrix" to detect it.

When it's disabled, the resistor array pulls the matrix all high, and the CD4019 will relay that, and then the 74'368 will return logical 0 when you read from it.

When it's enabled, the resistor array pulls the matrix low, except for whatever buttons are pressed, the CD4019 will relay the low voltage, and the 74'368 will return logical 1 for any buttons that aren't pressed.


Top
 Profile  
 
PostPosted: Thu Nov 23, 2017 11:02 am 
Offline
User avatar

Joined: Sun Jan 22, 2012 12:03 pm
Posts: 5899
Location: Canada
Ah1 Thank you, I missed the line that said a held key is 0. Well that's easy then. :)


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 3 posts ] 

All times are UTC - 7 hours


Who is online

Users browsing this forum: Majestic-12 [Bot], Yahoo [Bot] and 3 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group