What is the theory of PIC programmers
What is the theory of PIC programmers
What is the Theory of PIC programmers? (Both of software and hardware)
Re: What is the theory of PIC programmers
Serial or Parallel programmers describe the PC interface used not the programming method - all PIC microcontrollers are programmed serially. Serial programmers connect to the Serial port and Parallel programmers connect to the parallel port.
The signals used at the parallel port interface still generate serial data - this is why a parallel port programmer is no faster than a serial port programmer.
In fact the speed of programming is determined by the PIC programming algorithm and is much slower than any of the PC interfaces. In general programming a Flash PIC device is quite slow (16F877A 30 seconds).
Programming seems slow when you make minor code changes and want to see the result quickly but compare this to old style EPROMs - you used to remove the chip from the board and put it under a UV light for 30 minutes!
JDM serial port PIC programmer
The JDM serial port PIC programmer cleverly uses the serial port to provide a high voltage programmer that does not require an external power supply. Its cheap and easy to construct and is useful for programming one off chips but you have to insert and remove the chip that you are programming moving from the programmer to the development board.
The problem with these programmers is that they reference the programmer's ground to the -ve serial output voltage. So the programmer's ground reference (to the PIC chip) is -8V (or whatever negative voltage the serial port generates). This is done to get a voltage swing of >13V that can be regulated by a zener to about 13V.
In practice this means that you can not make any ICSP connection to your development hardware as you can not connect development ground to -8V! so you have to remove and insert the chip.
Read this article for more information about ICSP.
The signals used at the parallel port interface still generate serial data - this is why a parallel port programmer is no faster than a serial port programmer.
In fact the speed of programming is determined by the PIC programming algorithm and is much slower than any of the PC interfaces. In general programming a Flash PIC device is quite slow (16F877A 30 seconds).
Programming seems slow when you make minor code changes and want to see the result quickly but compare this to old style EPROMs - you used to remove the chip from the board and put it under a UV light for 30 minutes!
JDM serial port PIC programmer
The JDM serial port PIC programmer cleverly uses the serial port to provide a high voltage programmer that does not require an external power supply. Its cheap and easy to construct and is useful for programming one off chips but you have to insert and remove the chip that you are programming moving from the programmer to the development board.
The problem with these programmers is that they reference the programmer's ground to the -ve serial output voltage. So the programmer's ground reference (to the PIC chip) is -8V (or whatever negative voltage the serial port generates). This is done to get a voltage swing of >13V that can be regulated by a zener to about 13V.
In practice this means that you can not make any ICSP connection to your development hardware as you can not connect development ground to -8V! so you have to remove and insert the chip.
Read this article for more information about ICSP.
Re: What is the theory of PIC programmers
Thankz bro.