Re: Re: Re: BL2100 Expansion headers (LCD) to add extra IOs

Stan Hsu <stanley_hsu-/[email protected]>
Newsgroups gmane.comp.hardware.rabbit-semiconductor
Message-ID <[email protected]>
Hi Dave.
 
Thanks for the ideas...
 
Stan



On Wednesday, November 6, 2013 8:34 PM, "[email protected]" <[email protected]> wrote:
  
Stan,

That one is a little more complex.  You would need:

Analog conditioning for the A/D (op amps)
A/D converter (SPI interface)  Parallax makes some 2 and 4 channel.

SPI requires 4 data lines. (one input, 3 output).

You would need a 74HC245 on the data bus.  Then two 74HC541 to act as latches, one input; one output.  Some address decode.

Not a complicated system, but a number of chips.

--

Easy way.  If you can work with PIC (Microchip) controllers, use one with A/D and interface to the Rabbit with RS485 or 232.  That is faster and the work load for the A/D conversion is off loaded.

Dave

>Hi Dave.
> 
>I would like to add more than digital IO.  Any success with analog inputs?
> 
>Thanks.
> 
>Stan  
>
>On Wednesday, November 6, 2013 3:47 AM, "[email protected]"    wrote:
>  
>  
>The answer is yes.  I have several designs that do just this.
>
>Only limitation is the missing R/W line, so I have some ports as outputs and others as inputs.
>
>Let me know if you want schematics.
>
>Dave
>
>> I was wondering one thing.  We are thinking about making a small board to add on extra IOs and using it with the expansion headers on the BL2100.  I can see from the dwg that there is PE7, A0-A3, and DB0-Db7.  So it seems like I can not use this using AuxIO because the IO bus PA0-7 is not available at the header.
>> 
>> Just curious if anyone has ever tried to add IOs (analog and digital) to this by adding a board and trying to use the PE7 and also the DB0-DB7 available. 
>> 
>> Aux IO is not difficult to program but without it, it seems it will be much slower.  Dont know, I have not done much ASM so I do not know how fast doing 8 bit readings would be.
>> 
>> Just wanted to see if anyone out there has any experience trying to do this.
>> 
>> Thanks
>> 
>> Stan the man...
>> 
>> ------------------------------------
>
>


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