Programmer + serial

PSouzaJr · Joined: 25 Jul 2012 Posts: 2

Is there any PIC or other uC that make possible to use the serial port (COM1) and at same time make possible to re-write (reprogram or update the firmware) by, for example, the COM2.

Douglas Kennedy · Joined: 07 Sep 2003 Posts: 755 Location: Florida

Yes but it has issues. A PIC can have programmed into it a RS232 serial boot loader. It has conditions first there is a need for a level shifter aka MAX232 to bring the TTL serial of the PIC up to the rs232 spec and invert the data stream. Next you need a programmer to download the boot loader.
This is the catch 22 since you need to purchase or build a programmer before you can remove the need for a programmer by using a boot loader.
The boot loader most often is useful if you have dozens of versions of your software out in the field and your clients wish to avoid the expense of a hardware programming device ex USB-64. You send them PICs pre-programmed with you application and a built in boot loader. Later to update code you send them the code hex file and they using the bootloader install the update.