how to use clock oscillator?

[hemnath]

I have attached a circuit. Please go through it.

Here Q1 output is connected to MCU pin RA5. Why it is connected? How the crystal is configured?

Im using CCS C compiler. Normally i use the default line when crystal is connected to RA4 and RA5.
#use delay(clock=20000000)

But here Clock is connected to only RA5. Please help how to use it.

Thanks in advance

 

[wp100]

Hi,

The device ASF1 is not a crystal, it is an External Oscillator, a crystal and transistors/logic gates etc creating a waveform.
However what frequency that device is producing is not given

So you need to set the Config statement for EXT OSC.

However for the devices shown on that diagram wonder why the 690s Internal oscillator is not being used, its more that accurate enough.

 

[hemnath]

I want to use external oscillator. Attached is the datasheet. I want to use 20Mhz.

How to configure in CCS C compiler. Please help

 

[wp100]

Hi,

Yes, that chip looks suitable, though not sure in CCS C how you specify the config statements, #pragma ?
Believe you need to specify EC MODE.

Assuming you are looking to build that circuit using the SHT1x sensor, they are probably the most accurate temp/hum chips around but they are expensive and small and they can easily get damaged, as I found out the hard way.

You might want to consider the much cheaper DTH11 / 22 modules which are more robust in their construction, though not as accurate.

 

[hemnath]

Thank you very much for the suggestion.

Now im using DHT11 module. Is it possible to simulate DHT11 in proteus?