Configuration Settings
Device Settings
Since some devices have identical pin-out, as in the case of the AT90S8515 and the AT90S4414 devices, there is no need for a personality adapter for each of them. The automatic personality adapter detection ensures correct pin-out configuration of the AT90EM04 emulator chip. However, for selecting a specific device, enter the emulator options menu and select the device from the device list.

Clock Selection Settings
Many AVR microcontrollers have fuse bits for selecting the reset delay time. The reset delay is necessary for the clock oscillator to stabilize. The time it takes for the oscillator to stabilize depends on the crystal or the resonator. If an external clock source is used then the reset delay can be set to only a few clocks. The reset delay fuse bits (CKSEL/FSTART depending on device) can be set or cleared by a parallel or serial programmer in an actual device. In the emulator, they are set in the options menu.

For more information about the reset delay fuses, please refer to the datasheets.

Single Step Timers Setting
This setting allows single stepping of the timers if checked. If cleared the timers continue to count (if enabled) even after the program execution is stopped by a user break or breakpoint. All other peripherals (SPI/UART/EEPROM/PORTs) continue to operate when the program execution is stopped.

This feature allows cycle by cycle debugging of the counter value, which is useful for event timing. However, in many cases, stopping the counter operation while debugging might not be desired. One example is when the timer is used in PWM mode. Stopping the timer in this case might damage the equipment that is being controlled by the PWM output.

EEPROM Restore Setting
Some AVR devices have on-chip EEPROM data memory. The ICE200 emulates the EEPROM by using an SRAM replacement inside the AT90EM04 emulator chip. This is done to eliminate problems with EEPROM write endurance. However, by doing so, a new problem is introduced since a power loss on the target will result in loss of the data stored in the SRAM that emulates the EEPROM.

A split solution handles the power loss situation. First select the EEPROM restore option. Before removing the power, take a snapshot of the EEPROM contents by pressing the EEPROM snapshot button (Figure 4-12). This will tell the ICE200 main board to read all EEPROM data into a buffer. When power is switched off and then on again, the ICE200 will restore the contents of the buffer to the SRAM before starting code execution.

Reset Pin Setting (ATtiny12/13 only)
When selecting ATtiny12 an additional option selection appears in the emulator options dialog box. The ATtiny12 and ATtiny13 devices have a programmable fuse that lets the RESET pin function as an input pin (PB5). When the RESET pin is selected to be used as an input, the device is only reset at power-on. Refer to the ATtiny12/13 datasheet for more information.

See Also