Programming in circuit - Electronic Circuits Projects Diagrams Free

MrMikey83 · 2nd February 2005, 02:48 AM

The pins used for programming on an ATmega32...can I leave LED's and other devices plugged into those ports while programming? The reason I ask is because I want to use the outputs and plan on programming the chip many times even after inserting into my circuit.
~Mike

MrMikey83 · 2nd February 2005, 06:53 PM

I tried programming with an LCD display connected to Port B and it doesn't see the chiip. So I guess the answer is no.
~Mike

The Real MicroMan · 2nd February 2005, 07:36 PM

you need to design an isolation circuit. if your oins are outputs, use a diode before the rest of the circuit, if they are inputs, a high value resistor works welll. as long as you isolate the pins it should have no trouble programing

MrMikey83 · 2nd February 2005, 09:52 PM

I'm going to use PortB for an LCD output and the pins connected to the programming pins are the data pins. These pins would be outputs from the AVR so I should use diodes.
~Mike

MrMikey83 · 4th February 2005, 01:22 AM

Killed it today. I tried connecting an input and uppon trying to program it wouldn't recognize the chip. I disconnected the input and tried to prog and still no luck. Replaced chip and it worked so I guess the old one if fubar. I still have 3 more so hopefully I dont screw up too many more times.
~Mike

bmcculla · 4th February 2005, 03:32 PM

Resistors are also often used to protect the controller and programmer from each other. A resistor in series with the programming signal keeps the uC from pulling too much current if the programmer and the uC are in contention. If the programming speed isn't too fast the resistor doesn't cause any problems with programming.

I'll bet Atmel has an app not on this very problem.

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2nd February 2005, 02:48 AM	(permalink)
MrMikey83	Programming in circuit The pins used for programming on an ATmega32...can I leave LED's and other devices plugged into those ports while programming? The reason I ask is because I want to use the outputs and plan on programming the chip many times even after inserting into my circuit. ~Mike __________________ All Electronic components run on smoke. Let the smoke out and it no longer works. ~Tim Baker (Electronics Instructor at John A. Logan College)

2nd February 2005, 06:53 PM	(permalink)
MrMikey83	I tried programming with an LCD display connected to Port B and it doesn't see the chiip. So I guess the answer is no. ~Mike __________________ All Electronic components run on smoke. Let the smoke out and it no longer works. ~Tim Baker (Electronics Instructor at John A. Logan College)

2nd February 2005, 07:36 PM	(permalink)
The Real MicroMan	you need to design an isolation circuit. if your oins are outputs, use a diode before the rest of the circuit, if they are inputs, a high value resistor works welll. as long as you isolate the pins it should have no trouble programing

2nd February 2005, 09:52 PM	(permalink)
MrMikey83	I'm going to use PortB for an LCD output and the pins connected to the programming pins are the data pins. These pins would be outputs from the AVR so I should use diodes. ~Mike __________________ All Electronic components run on smoke. Let the smoke out and it no longer works. ~Tim Baker (Electronics Instructor at John A. Logan College)

4th February 2005, 01:22 AM	(permalink)
MrMikey83	Killed it today. I tried connecting an input and uppon trying to program it wouldn't recognize the chip. I disconnected the input and tried to prog and still no luck. Replaced chip and it worked so I guess the old one if fubar. I still have 3 more so hopefully I dont screw up too many more times. ~Mike __________________ All Electronic components run on smoke. Let the smoke out and it no longer works. ~Tim Baker (Electronics Instructor at John A. Logan College)

4th February 2005, 03:32 PM	(permalink)
bmcculla	Resistors are also often used to protect the controller and programmer from each other. A resistor in series with the programming signal keeps the uC from pulling too much current if the programmer and the uC are in contention. If the programming speed isn't too fast the resistor doesn't cause any problems with programming. I'll bet Atmel has an app not on this very problem.