Electronics -- Atmel/AVR-programming: AVR Circuit
AVR RISC Programmer: (Quick) Electronic Circuit
This is really a trivial (quick solution) circuit as it applies
only half a dozen
parts (two resistors, one CMOS chip, a socket, a switch, some cable;
see further down for a more advanced
I provide two designs here which were tested and verified to work (but
come with absolutely no warranty for principal reasons).
Download the electronic circuit sheets:
Permission to copy and use these sheets is hereby granted provided credit is given where it is due.
AVR RISC Programmer: (Advanced) Electronic Circuit
The quick and easy-to-build circuit presented on this page worked for me but it clearly has its drawbacks: The button switch may bounce and there is no way to switch into running mode. Hence, I now recommend to use a more advanced supply circuit which replaces in the below (quick) ciruit all those parts on the right handside of the microcontroller (i.e. IC2(A), R1,2, D1, S1, SUPPLY).
The Technical Details
I will discuss the ATMega161 sheet here:
The large part in the center is the actual ATMega161 AVR RISC controller
which is best put on a 40 pin precision socket (or some quick
The CD40106 Schmitt trigger needs some explanation. The Atmel AVR RICSs are put into programming mode by applying +12V to the RESET line (while still using 5V supply voltage), so you need 5V and 12V supply voltages for the device. If you close the switch, the Schmitt trigger (you can use an inverter or a CD4011 as well) goes HIGH, i.e. to +12V (look at the supply pins; this is the reason why you need the plain 4xxx series CMOS chips which can be used with up to 15 (or 18) Volts and no HC, HCT or AC variants). To sum up: The microcontroller is in programming mode as long as the switch is closed.
The diode D1 and the resistor R2 are used to keep the 12V level off the Latch16Bit board's channel B input (because that would destroy the 74HC573 latch on that board).