Re: TI-H: Port Expander I
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Re: TI-H: Port Expander I
You were talking about a 4414 or 8515 for lots of I/O. All the expander
needs to do is:
Write: rcall get_ti_nib
out PORTA, BYTE ;just a nibble.
rcall get_ti_byte
out PORTB, BYTE
rcall get_ti_byte
out PORTC, BYTE
rcall get_ti_byte
out PORTD, BYTE
rjmp Write
or if you wanted bi directional
Main: rcall get_ti_byte
cp $01 ;read lines
breq READ
cp $02 ;write lines
breq WRITE
rjmp Main ;error or done with command
Wouldn't it be much more fun to take 3 data lines on the 8515 and turn
those into 8? It would be harder though. Then you'd have a total of 64 I
or O for about $4 and for $8 you could have an easy 64 of I/O. And thats
figuring you would be using 4 I/O lines for the TI and 2 for read/write
LEDs.
You could even add a 4 bit counter and have up to 16 Shift registers per 3
8515 pins. Lets say 8 are read and 8 are write. Thats 512 I/O lines.
And that would only cost....hm..let me grab my 92...$64... :)
Oh well, it would be fun. :) I'd like to have a 512bit expander. :)
>$13??? a 1200 is about 3 bucks
>
>>Date: Tue, 14 Jul 1998 08:54:32 -0800 (AKDT)
>>To: ti-hardware@lists.ticalc.org
>>From: Grant Stockly <gussie@alaska.net>
>>Subject: Re: TI-H: Port Expander I
>>Reply-To: ti-hardware@lists.ticalc.org
>>
>>
>>Well, a $13 chip could do the same thing as 8 $.50 chips and a few
>other
>>cheep parts. :)
>>
>>>Yeah, probably but I wanted to design something with the AVR MCU's.
>>>
>>>>Date: Tue, 14 Jul 1998 07:23:17 -0800 (AKDT)
>>>>To: ti-hardware@lists.ticalc.org
>>>>From: Grant Stockly <gussie@alaska.net>
>>>>Subject: Re: TI-H: Port Expander I
>>>>Reply-To: ti-hardware@lists.ticalc.org
>>>>
>>>>
>>>>Mel would probably say just use a bunch of 8bit I/O expanders and a
>>>counter
>>>>for $2. :)
>>>>
>>>>>I have designed a port expander(PEI) for the TI link port. Features
>>>>>include:
>>>>>
>>>>>-Atmel AT90S1200 MCU
>>>>>-8 data lines. plus a another for misc use
>>>>>-3 address line, for connection of up to 8 modules
>>>>>-seperate power supply
>>>>>
>>>>>there will be 2 kinds of modules. The first will have it's own
>>>address
>>>>>decoder for plugging directly connecting into the Expansion Module
>>>>>Port(EMP), and the other will plug into a board that already has the
>>>>>address decoders onboard.
>>>>>
>>>>>If anyone is interested in the schematics drop me a line. It's a
>>>zipped
>>>>>file, and the pics are jpg. It might be hard to read since I drew
>>>them
>>>>>out on paper and then scanned them in.
>>>>>
>>>>>Port Expander II
>>>>>thes will have a 4414 or 8515 as it's controller. It will have 4-6
>>>>>address lines for 16, 32, or 64(might be overkill and one hell of a
>>>>>power user but what the hell), and 26-28 data lines.
>>>>>
>>>>>
>>>>>Matt Butch
>>>>>
>>>>>______________________________________________________
>>>>>Get Your Private, Free Email at http://www.hotmail.com
>>>>
>>>>
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>>>>
>>>>To Subscribe to the ACplay mailing list, please send a message to
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>>>>To talk to me direct, I'm 'weridguy' on AOL IM service. I don't have
>>>an
>>>>AOL account, just the IM thing.
>>>>
>>>>Thanks.
>>>>
>>>>
>>>>
>>>
>>>
>>>______________________________________________________
>>>Get Your Private, Free Email at http://www.hotmail.com
>>
>>
>>---
>>
>>To Subscribe to the ACplay mailing list, please send a message to
>>gussie@alaska.net with the subject "SUBSCRIBE ACPLAY"
>>
>>To get an e-mail every time http://gussie.alaska.net is updated, please
>>send a message to gussie@alaska.net with the subject "SUBSCRIBE
>ACNOTIFY".
>>
>>To talk to me direct, I'm 'weridguy' on AOL IM service. I don't have
>an
>>AOL account, just the IM thing.
>>
>>Thanks.
>>
>>
>>
>
>
>______________________________________________________
>Get Your Private, Free Email at http://www.hotmail.com
---
To Subscribe to the ACplay mailing list, please send a message to
gussie@alaska.net with the subject "SUBSCRIBE ACPLAY"
To get an e-mail every time http://gussie.alaska.net is updated, please
send a message to gussie@alaska.net with the subject "SUBSCRIBE ACNOTIFY".
To talk to me direct, I'm 'weridguy' on AOL IM service. I don't have an
AOL account, just the IM thing.
Thanks.
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