pic16f819 interface with computer serial port

[d@nny]

is pic16f819 able to directly connect with pc serial port or i need the ic as max232?

 

[alexan_e]

Read

Most microcontrollers run on a single supply voltage, and 99 out of 100 times, that voltage is +5 volts. In rough terms, logical 1 on these devices indicates that +5 is the voltage on the output pin. Logical 0 specifies that 0 volts is on the line.

The RS-232-C standard specifies that the voltage on the wire for sending a logical 0 are from +5v to +15v. The voltage for sending a 1 are from -5v to -15v. Most microcontrollers not capable of generating these voltages. So, to connect a microcontroller SCI port to a true RS-232 device, you need to convert the TTL voltages of 0 and +5 into voltages between about -10 volts and +10 volts.

In general the serial port standard in the PC side needs higher voltages (positive & negative) to work so you need some king of interface between the pc and mcu

Alex

 

[bigdogguru]

In general the serial port standard in the PC side needs higher voltages (positive & negative) to work so you need some king of interface between the pc and mcu

Alex

Not only does the PC need higher voltages ranges, both negative and positive, as Alex pointed out.

Remember, the PIC itself will be subjected to these extraordinarily HIGH POSITIVE and NEGATIVE Voltages from the PC's RS-232 Port.

is pic16f819 able to directly connect with pc serial port or i need the ic as max232?

Therefore, directly connecting a PIC to a PC's RS-232 Port could have disastrous results for the PIC, both in exceeding pin voltage and current levels.

In short, doing so could easily result in a damage/dead PIC.

 

[thirugnanam.ram]

Obviously max 232 is needed.

 

[upand_at_them]

Or two transistors.

 

[alexan_e]

The transistor solution is inferior compared to the max232 solution.
This was discussed in an older thread https://www.edaboard.com/threads/200678/

Alex