Atmel microcontrollers question???

[auto_mitch]

hi!
i am new with microcontrollers and i have some questions:
1) What is the meaning of L at some avr models?
2)Can i use a serial port connector and via Max232 to program an avr microcontroller by pc's RS-232 port???
thanks guys,anyway!!!

 

[bmcculla]

1) the L means that is it a low voltage part and can run at 3V instead of 5. The low valtage parts usualy run slower.

2) Some AVRs have a section of code set asside for a bootloader. Once you program in a bootloader you can program the part with any interface. The bootloader lets you continue to execute instructions while the part programs its own memory - where the data is coming from is up to you. I don't think there are any parts that have a preprogrammed bootloader though - you still need a programmer to program the bootloader code. Some of Atmel's older 8051 parts have built in bootloader code for RS232 if you want something that is ready to go with a bootloader.