AVR microcontroller programmes can be classified by programming method – how program is loaded in to microcontroller from computer.
One is Parallel programmer (byte by byte). This isn’t popular programming method. But it is fast programming method. Using parallel programmer you can set fuses which will protect from using ISP method. But main disadvantage of parallel programming is that you have to remove microcontroller from circuit. This might be used when producing series of same kind preprogrammed microcontrollers before they are soldered in to board.
Parallel programmer can program RESET pin to be used as fully functional I/O line this is why ISP cannot be used after this procedure. Restoring of RESET function can only be done with Parallel programmer.
Serial programming interface is more convenient for electronics hobbyist. Main benefit of ISP programmer that you can program microcontroller directly on board. ISP programmers can be connected to COM or LPT port. COM port becoming obsolete as it require additional circuitry, while LPT programmer can be as simple as few wires connecting AVR to LPT port.
Popular ISP adapters:
-
http://elm-chan.org/works/avrx/avrx_com.png. Simplified and Buffered.
-
http://www.lancos.com/e2p/avrisp-stk200.gif. Most popular AVR-ISP for LPT port.
-
http://toolbox.xilinx.com/docsan/3_1i/data/common/jtg/figures/images/x7557.gif. Download cable for Xilinx CPLD/FPGA.
- Altera ByteBlasterMV. Download cable for Aletra PLD
