Renesas R8C A/D converter question?

[osmanpasali]

Hi,
Although i connot get answers to my questions i continue asking......
Can i connect VCC pin of R8C/1B to 3.6V and Vref pin to 5V? I mean Can Vref of A/D converter be connected to a source greater than Vcc of the MCU?

 

[boseji]

Hello,

Dont loose heart.

Those who keep Trying Never Loose!!

I am a R8C user too. We I have used R8C/13.
You can either use the internal ref or use the VCC for external ref. But mind it the Vref < VCC - 0.5 else I have faced a lot of problem in one of my projects. I was trying to make a scope to show the Voltage signal that I measure. I was having a lot of the offset problems. Then I simply attached a 220R resistor in series with the Vref. This worked. Probably you too can try it out.

Best of Luck!!

 

[osmanpasali]

thank you for your answer.. i will try it. by the way how can i use internal reference?

 

[boseji]

Hello,

A mistake from my side. The AVCC itself would become the Reference. This facility of Internal reference is only available in a few of the M16s I have used. So I mixed it with R8C. You require to use the AVCC with the levels of 3.3V or 5V. Also keep in mind that the Input ADC signal should not be greater than this value.

Best of Luck!!