4

AVR32924

32156A-AVR-01/11

3.2 Power supply

The kit is powered via the USB connector, which leaves two options to power it:

Connect the kit either to a PC through a USB cable or to a 5V USB power supply

(AC/DC adapter).

The 5V is regulated down to 3.3V with an onboard LDO regulator, which provides

power to the entire board. The Atmel AT32UC3L064 is powered by 3.3V, but if 1.8V

operation is desired, some modifications to the board are needed. This includes

replacing the regulator with one that delivers 1.8V output and rerouting the power to

the device (see schematic for explanation). As some of the other ICs on the Atmel

UC3-L0 Xplained require 3.3V to operate correctly, these devices have to be removed

also.

3.3 Measuring the AT32UC3L064 power consumption

As part of an evaluation of the AT32UC3L064, it can be of interest to measure its

power consumption. The two-pin header with a jumper mounted on it is the only

connection between the common power plane VCC_P3V3 and the VCC_MCU_P3V3

power plane. By replacing the jumper with an ampere meter, it is possible to

determine the current consumption of the AT32UC3L064. To locate the power

measurement header, please refer to Figure 3-1.

WARNING

Do not power the board without having the jumper or an ampere meter

mounted. Otherwise, the device may be damaged.

3.4 Programming the AT32UC3L064 through the UART-to-USB gateway

The AT32UC3L064 can be programmed through the UART-to-USB gateway. This

can be accomplished using the UART boot loader preprogrammed in the device.

Press and hold the mechanical button switch while powering up the board to enter the

boot loader, and use 32-bit AVR Studio to set up a programming connection to the

device.

NOTE

If the default board controller firmware is replaced, programming of the

AT32UC3L064 may not be possible as the UART-to-USB functionality might be

missing.

NOTE

If any external programming tool is used on the AT32UC3L064, the boot loader might

be erased, and it will not be possible to program the device through the UART-to-USB

gateway. In this case the boot loader has to be restored with an external

programming tool.

3.5 Communication through the UART-to-USB gateway

The AT32UC3L064 UART is connected to a UART on the Atmel AT32UC3B1256.

The AT32UC3B1256 UART is communicating at 57600 baud, using one start bit,

eight data bits, one stop bit, and no parity.

When the AT32UC3B1256 device is enumerated (connected to a PC), the data

transmitted from the AT32UC3L064 is passed on to a (virtual) COM port. This means

that it is possible to use a terminal program to receive the transmitted data on a PC.

Similarly data transmitted from the PC COM port is passed on to the AT32UC3L064

UART through the gateway.