Does the 1.1V analog ref work on the Attiny85 ?

Using Arduino Microcontrollers
1

My project works great on the UNO but really having just 1 analog in and 1 PWM out. i do use the 1.1V analog ref though, does this also work on the '85 ?

2

Yup. The Attiny85 has a 1.1V bandgap reference which can be used as an analog reference.

It can be enabled as the reference for the ADC as follows:

ADMUX &= ~((1<<REFS0)|(1<<REFS2));
ADMUX |= (1<<REFS1);
3

can't i just use analogReference() ? or is it not supported by the IDE ?

4

Short answer: you possibly could use analogReference().
Long answer: you will need to use a different core library set for the Attiny series. It depends what has been implemented.

5

well I've got the high low tech thing to get the tiny's working, is there more stuff I need to have put in ?

6

sparkylabs:
My project works great on the UNO but really having just 1 analog in and 1 PWM out. i do use the 1.1V analog ref though, does this also work on the '85 ?

A glance at the datasheet would tell you that it has 1.1V and 2.56V references.

sparkylabs:
can't i just use analogReference() ? or is it not supported by the IDE ?

It's nothing to do with the IDE, it will depend on the core you installed (most of them are quite complete...)

7

core ? do you mean the support files ?

8

sparkylabs:
core ? do you mean the support files ?

You have to install something like this before you can use an ATtiny with the IDE:

https://code.google.com/p/arduino-tiny/

There's a few different ones out there and we don't know which one you installed.

9

I'm using: http://hlt.media.mit.edu/?p=1229 which does not list it so I guess I'm out of luck unless I can use C code directly ?

10

sparkylabs:
I'm using: http://hlt.media.mit.edu/?p=1229 which does not list it so I guess I'm out of luck unless I can use C code directly ?

Direct programming AVR chips is easy. For the ADC you only need to manipulate three registers.

ADMUX = XXXX;   // Select a source
ADCSRA = 0xd0;  // Start a conversion
while ((ADCSRA&0x10)==0) {
  // Wait for conversion to complete
}
int val = ADC;  // Get result

(Or something like that ... I just typed that with no testing, see datasheet...)

11