ATmega128 external clock recovery - Revision history

Ivc: /* Fix */

2011-04-07T18:28:17Z

Fix

← Older revision		Revision as of 18:28, 7 April 2011
Line 2:		Line 2:

	== Fix ==		== Fix ==
	To recover the micro with stuck in "External clock" mode, is to connect a 1-3MHz function generator to pin 24 on the ATmega128. The ~~micro~~ should then be ~~revived~~ on the next power cycle.		To recover the micro with stuck in "External clock" mode, is to connect a 1-3MHz function generator to pin 24 on the ATmega128, here it's another micro. The ATmega128 should then be possible to program and boot normally on the next power cycle.

	=== Connection ===		=== Connection ===

Ivc: /* Program */

2011-04-07T18:25:44Z

Program

← Older revision		Revision as of 18:25, 7 April 2011
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	# The micro is now recovered and the external clock can be removed, reset to try		# The micro is now recovered and the external clock can be removed, reset to try

	[[Image:ATmega128_external_clock_spi_speed.png\|~~300px~~]] [[Image:ATmega128_external_clock_recovery_restore.png\|~~300px~~]] [[Image:ATmega128_external_clock_recovery_success.png\|~~300px~~]]		[[Image:ATmega128_external_failed.png\|200px]] [[Image:ATmega128_external_clock_spi_speed.png\|200px]] [[Image:ATmega128_external_clock_recovery_restore.png\|200px]] [[Image:ATmega128_external_clock_recovery_success.png\|200px]]

	=== Function generator ===		=== Function generator ===

Ivc: /* Program */

2011-04-07T18:22:37Z

Program

← Older revision		Revision as of 18:22, 7 April 2011
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	# The micro is now recovered and the external clock can be removed, reset to try		# The micro is now recovered and the external clock can be removed, reset to try

	[[Image:ATmega128_external_clock_spi_speed.png\|~~400px~~]] [[Image:ATmega128_external_clock_recovery_restore.png\|~~400px~~]] [[Image:ATmega128_external_clock_recovery_success.png\|~~400px~~]]		[[Image:ATmega128_external_clock_spi_speed.png\|300px]] [[Image:ATmega128_external_clock_recovery_restore.png\|300px]] [[Image:ATmega128_external_clock_recovery_success.png\|300px]]


	=== Function generator ===		=== Function generator ===

Ivc: /* Fix */

2011-04-07T18:22:03Z

Fix

← Older revision		Revision as of 18:22, 7 April 2011
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	# Once the programming mode is successful, go to the Fuses tab, unpick CLOPT if selected, and pick "Int. RC Osc. 1MHz; Start-up time: 6 CK + 64 ms", click program		# Once the programming mode is successful, go to the Fuses tab, unpick CLOPT if selected, and pick "Int. RC Osc. 1MHz; Start-up time: 6 CK + 64 ms", click program
	# The micro is now recovered and the external clock can be removed, reset to try		# The micro is now recovered and the external clock can be removed, reset to try

			[[Image:ATmega128_external_clock_spi_speed.png\|400px]] [[Image:ATmega128_external_clock_recovery_restore.png\|400px]] [[Image:ATmega128_external_clock_recovery_success.png\|400px]]


	=== Function generator ===		=== Function generator ===

Ivc: /* = Arduino */

2011-04-07T18:20:20Z

= Arduino

← Older revision		Revision as of 18:20, 7 April 2011
Line 19:		Line 19:

	=== Function generator ===		=== Function generator ===
	=== Arduino ==		=== Arduino ===
	Paste into the Arduino editor, compile and upload.		Paste into the Arduino editor, compile and upload.

Ivc: /* = Arduino */

2011-04-07T18:20:10Z

= Arduino

← Older revision		Revision as of 18:20, 7 April 2011
Line 19:		Line 19:

	=== Function generator ===		=== Function generator ===
	==== Arduino ===		=== Arduino ==
	Paste into the Arduino editor, compile and upload.		Paste into the Arduino editor, compile and upload.

Ivc: Created page with "If you accidentally programmed the Fuses to use the "External Clock" instead of "External crystal" in the SUT_CKSEL setting, the microcontroller is temporarily rendered useless...."

2011-04-07T18:19:52Z

Created page with "If you accidentally programmed the Fuses to use the "External Clock" instead of "External crystal" in the SUT_CKSEL setting, the microcontroller is temporarily rendered useless...."

New page

If you accidentally programmed the Fuses to use the "External Clock" instead of "External crystal" in the SUT_CKSEL setting, the microcontroller is temporarily rendered useless.

== Fix ==
To recover the micro with stuck in "External clock" mode, is to connect a 1-3MHz function generator to pin 24 on the ATmega128. The micro should then be revived on the next power cycle.

=== Connection ===
# Remove the crystal and the capacitor connected to pin 24, named XTAL1.
# Get another ATmega based microcontroller, I used a Arduino Uno with an ATmega323, download and program it with the code below
# Connect the other micro by connecting ground to ground on the ATmega128, usually pins 53 or 22,
# And connect PD3, digital pin 3 on Arduino Uno, to pin 24 on the ATmega128, check the datasheet to find the correct pin
# Connect the AVR programmer, I used a USBTinyAVR programmer that mimics the official AVRISP programmer

=== Program ===
# Open AVR Studio 4 and click the program icon in the tool bar to initialize a connection, select AVRISP and Auto, or the correct type and port for the programmer
# Once connected to the programmer, set the ISP speed to around 100-125kHz, I have 112.5kHz, click write
# If the entering programming fails, as it usually does, try resetting the other controller and the ATmega128, on that order
# Once the programming mode is successful, go to the Fuses tab, unpick CLOPT if selected, and pick "Int. RC Osc. 1MHz; Start-up time: 6 CK + 64 ms", click program
# The micro is now recovered and the external clock can be removed, reset to try

=== Function generator ===
==== Arduino ===
Paste into the Arduino editor, compile and upload.

void setup()
{
cli();
DDRD = 0xff;
}

void loop()
{
while (1) {
// uncomment the delay and comment out cli() to try with a led to find the correct pin
PORTD |= 0x8;
//delay(100);
PORTD &= ~0x8;
//delay(100);
}
}

==== AVR ====
Untested code, but it should work fine, compile and upload in AVR Studio or Eclipse.
#include <avr/io.h>
void main(void)
{
cli();
DDRD = 0xff;
while (1) {
PORTD |= 0x8;
PORTD &= ~0x8;
}
}

== References ==
* [http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1230286016/30 Maximum pin toggle speed]
* [http://arduino.cc/en/Hacking/Atmega168Hardware Arduino ATmega 168 hardware]