AVR-Chat

I should add that all of the special function pins (in most
chips) also have a general purpose function. That is, they
are multiple use. 

Jim


On Wed, 22 Nov 2006 00:15:14 -0500
 "Jim Wagner" <jim_d_wagner@applelinks.net> wrote:
> Hardware functions such as PWM are hard-coupled to
> specific
> pins.  You can generate software PWM that uses any pin.
> 
> Likewise, UART, SPI, TWI, ISP, etc, are all hard-coupled
> to
> specific pins. Again, you can implement any of  these
> things in software on almost any pin. But, its REALLY
> hard
> to use internal UART hardware with arbitrary Tx and Rx
> pins.
> 
> Jim
> 
> 
> On Tue, 21 Nov 2006 04:48:39 -0000
>  "luthjej" <luthjej@yahoo.com.au> wrote:
> > Hi all,
> >    I'm new to this group, predominantly because I've
> > always used PIC's
> > for control applications - but I've decided that it's
> > time to give the
> > AVR a whirl; the feature list on the mega series AVR's
> is
> > just too
> > good to pass up! :)
> > 
> > For my first design, I'm using a mega8 MCU for a closed
> > loop
> > automotive control circuit, nothing terribly fancy, but
> > I'm just
> > wondering about port allocations in terms of digital
> > I/O's - I know
> > that on the older MCU's (PIC12Fxx, HC11 etc) there were
> > significant
> > restrictions on what ports can be used for what
> function
> > (i.e. PWM was
> > restricted to only a few pins, some ports were input or
> > output only etc).
> > 
> > So, just before I go and get the PCB printed up, I was
> > just hoping
> > that the knowledgable could cast their eye on my pin
> > allocations that
> > I'm not doing anything impossible (or anything that's a
> > particularly
> > bad idea! :).
> > 
> > I've read the data sheet cover to cover, and haven't
> come
> > across
> > anything yet, although I'm still a bit vague as to
> which
> > pins can
> > actually support PWM and whether different pins on
> > different ports can
> > be allocated to different functions at the same time
> (e.g
> > ADC Port -
> > can I do digital logic in, logic level out AND ADC
> > conversion - all at
> > the same time?
> > 
> > PB0   - Out Piezo Buzzer Out (Direct Drive 20mA Max)
> > PB1,2 - Out PWM Drive 1,2 (to FET driver IC)
> > PD0,1 - In/Out RS232 Out via MAX232
> > PD2-7 - LCD Display Out
> > PB6   - Out SPI Device Slave Select
> > PB7   - In Keyboard (switches via 1N914's across PD2-7)
> > PC0   - 0-5v analogue in (for ADC use)
> > PC1-3 - +12v logic in (direct connect via 1k resistor)
> > PC4   - 0-5v analogue in (for ADC use)
> > PC5   - FET Drive (on/off) via FET Driver IC
> > 
> > MISO, SCK, MOSI - SPI Bus & ICP Header (Also LED via
> 500R
> > resistor to
> > indicate SPI activity)
> > 
> > AREF,AVCC,VCC - Regulated +5v (no decoupling - direct
> > connect)
> > 
> > 
> > 
> > Thanks in advance for your help.
> > 
> > 
> > Jon
> > 
> > 
> > 
> 
>
---------------------------------------------------------------
> The Think Different Store
> http://www.thinkdifferentstore.com/
> For All Your Mac Gear
>
---------------------------------------------------------------

---------------------------------------------------------------
The Think Different Store
http://www.thinkdifferentstore.com/
For All Your Mac Gear
---------------------------------------------------------------