I am using PIC16F1503 for my automotive application. I want to understand few things:-



1)I have gone through through the schematic present in the "https://ww1.microchip.com/downloads/en/DeviceDoc/50002295A.pdf". In this, PIC 16F1503 is not having external oscillator. I want to know if it is possible to connect external crystal oscillator to PIC16F1503. If yes, which are the pin numbers to which external crystal oscillator can be connected? What is the difference if micro-controller runs on external crystal or on internal oscillator?

2)How to implement UART on PIC16f1503 ? I did not find any RX and TX pin on PIC16F1503.
3)How to implement OTA on PIC16f1503?

 

The manual shows the details of the oscillator, up to 16mhz internal or 20mhz external.
Do you have the manual?
see 5-2 on p44

 

2)How to implement UART on PIC16f1503 ? I did not find any RX and TX pin on PIC16F1503.

The '1503 does not include a UART. You could do it using the bit-bang method but it's a lot more work.

 

Seek a suitable PIC from the selection chart that has the features you need.

 

If you have to create your own UART, I would say this is the wrong chip to be using. It's just not worth the trouble, and there are lots of alternatives for around the same cost which have it built-in.

 

Is PIC16F1503, a good choice for automotive applications?

 

Microchip have a good part selector which helps to find parts with particular attributes appropriate for your needs.
https://www.microchip.com/maps/main.aspx