Atmel AVR ATmegaICE, User Manual

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ATmegaPOD
3-2 AVR
®
ATmegaICE User Guide
3.1 Voltage
Regulation for
Port Pins
If the target system uses its own power supply, the output voltage must be set to the
voltage in the target system. The jumpers J200-J202 are used for this purpose. The
interpretation of the different settings of these jumpers is shown in Figure 3-2.
Figure 3-2. Jumper Setting
3.2 Clock Setting
The external clock system can be set to use either an external crystal or an external
clock signal.
To use an external crystal, select “External Oscillator” in the “Emulator Options” menu in
AVR Studio, and select an appropriate frequency range for the mounted crystal. Note
that the selected frequency range may not correspond to the crystal frequency due to
load capacitors and/or stray capacitors in the system. J300 must be open when using an
external crystal.
If an external clock signal is used (on pin XTAL1), jumper J300 must be mounted. This
setting also requires the user to select External Oscillator in the Emulator Options menu
in AVR Studio.
ATmegaICE also has a very accurate programmable internal clock which can be used
for emulation. Select this clock by choosing Internal Oscillator in the Emulator Options
menu in AVR Studio. Setting of J300 on the ATmegaPOD and crystals and clock signals
in the user application are insignificant when the internal oscillator is selected.
3.3 Timer Oscillator
Setting
In order to enable the Timer oscillator, jumper J351 must be mounted. When J351 is
mounted, the setting of J350 determines whether to use an external clock signal or the
local oscillator. If J350 is mounted, the external clock signal is used (on pin TOSC1).
If J350 is not mounted, an external crystal is expected to be mounted between the
TOSC1 and TOSC2 pins. When an external crystal is used (J350 not mounted), jumpers
J352 and J354 should be used to indicate the frequency range of the oscillator. The
interpretation of the different settings for these jumpers is given in Table 3-1.
Target VCC J202 J201 J200
2.7 - 2.9 V
3.0 - 3.3 V
3.4 - 3.7 V
3.8 - 4.1 V
4.2 - 4.5 V
4.6 - 4.8 V
4.9 - 5.1 V
5.2 - 5.5 V
Table 3-1. OSC frequency range jumper settings
J354 J352 Frequency Range
- - 10 kHz - 100 kHz
- Mounted 100 kHz - 1 MHz
Mounted - 1 MHz - 5 MHz
Mounted Mounted 5 MHz - 10 MHz