12f675 and midi!

[Ingvar]

You set the use of an exernal oscillator in your programmer software, in your case you should look for HS oscillator. To make GP0 and 1 analog inputs, GP2 digital output and ADconverter 10bit, you should probably(never used the 12F675) use ....

TRISIO = %00000011
ANSEL = %00110011
ADCON0 = %10000001

ADvalue VAR WORD

ADCIN 0,ADvalue ' Read channel 0
ADCIN 1,ADvalue ' Read channel 1

[Alaskanphoenix]

I want to use gp0 and gp1 as analog inputs and gp3 as digital out to send midi messages:

DEFINE OSC 20
DEFINE DEBUG_BAUD 31250 ' midi baud rate
DEFINE DEBUG_REG gpio ' Set Debug pin port
DEFINE DEBUG_BIT 2 ' Set Debug pin bit
DEFINE DEBUG_MODE 0

adval var byte ' Create adval to store result
ANSEL = %00000011 ' ----DDAA
CMCON = 7 ' Analog comparators off

loop: ADCIN 0, adval ' Read channel 0 to adval
debug $b0,$00,adval
Pause 250 ' Do it all about 10 times a second
Goto loop ' Do it forever

End

how can i limit the results of analog inputs between 0-127?

Thanks a lot

[mischl]

divide adval by 2

adval = adval / 2
adval = adval >> 2

[Alaskanphoenix]

Thank you all very much!
It finally works!

I use the Hs oscillator and it works ok!

One last question, why if i connect a pot in gpio.0 and rotate it the numbers don't start from 0 but from $7f, go to 0 and arrive to $7f?

i use adval >> 2 to limit till $7F

Thanks

[mischl]

the pot values goes from 127 to 0 instead 0 to 127?

then change the plus and minus on your pot, that changes the direction

[Alaskanphoenix]

The pot starts from $7f, decreases till 0 and goes to $7f in the same direction!
But i used advar = advar >> 1 instead of >> 2, because the second starts from $3f to 0 to $3F!

Why?

[TonyA]

I'm also into MIDI. I've made a midi sender with the 18F452 and was wondering about the 12F683. But since it didn't have HSEROUT I wasn't sure if it would work. So it seems it can work with serout using a 20 Mhtz xtal?

Something I'm confused about however is the setting up of the ANSEL.
I see that in the example above by Ingvar there are 2 bits that are set high along with the appropriate pins: like this ANSEL %00110011, but in Allaskan's example he just does this: ANSEL %00000011

So GPIO.0 and GPIO.1 are analog inputs, but what do the 1's in position 4 and 5 represent?
What is the ADCON0 doing?

Also, why do you have to disable the analog comparators?

Thank,
Tony