Todo: Create a
new Atmel | START Project, where CLOCK, ADC, and USART modules are
configured.
- Open Atmel Studio 7.
- Create a new Atmel | START project in Atmel Studio by
- Open the CREATE NEW PROJECT
window by selecting File->New->Atmel START project.
- Select the target hardware by
entering 817X in the Filter on device... text box and selecting
ATtiny817 Xplained Pro from the list.
- Create the project by clicking
CREATE NEW PROJECT as shown in Figure 1.
Figure 1. CREATE NEW PROJECT
Info: The
MY SOFTWARE COMPONENTS window should appear.
- Rename the project by clicking MY
PROJECT in the MY SOFTWARE COMPONENTS window and select Rename
Component as shown in Figure 2.
Figure 2. Rename Component
Info: The RENAME COMPONENT window should appear.
Enter the project name, for example,
ADC_Training, in the
popped up
RENAME COMPONENT window and click
Rename to close it.
Note: This step is optional to rename the
project name.
- Add ADC and USART drivers to the project
by
- Open the ADD SOFTWARE
COMPONENTS window by clicking

- Expand Drivers by clicking
+
- Select ADC and USART by clicking
, as shown in Figure 3Info: ADC and USART will be highlighted as
the selected modules as shown in
Figure 3.
Figure 3. Add RTC and USART
Modules
- Add the drivers to the project by
clicking the Add component(s) button.
- Open the CLOCK CONFIGURATOR window
by clicking
on the navigation tab at the left side of the window as shown in Figure 4.
Figure 4. Clock Configuration
Info: The
CLOCK CONFIGURATOR window consists of oscillators and clock sources of
different types. Required clock source can be selected and the calculated output
frequency will be displayed.
- The OSCILLATORS
section displays the oscillators available for the selected device. The
oscillator parameters can be configured by clicking
to
select Settings Dialog.
- The SOURCES section is
used to configure clock frequency by selecting input signal and prescaler
settings.
- Configure the Main Clock (CLK_MAIN) clock
source by
- Open the CLOCK SETTINGS window by clicking
as shown
in Figure 4.
- Select 20 MHz as the Main
Clock Source from the drop-down menu.
- Select 4 as the Prescaler division from the drop-down menu.
- Close CLOCK SETTINGS by
clicking the Close button.
Figure 5. Clock Settings
Info: For this application, 20 MHz OSC is
chosen as the main clock source with prescaler division equal to 4. The resulting
CPU clock frequency is 5 MHz.
For quick reference, clicking
next to
each configuration will provide the data sheet description of individual bit
settings.
- Return to MY SOFTWARE COMPONENTS,
by clicking
in the navigation tab on the top of the left side of the window.
- Configure the ADC module by following the steps in Figure 6:
Figure 6. ADC Configuration
- Open the configuration menu for ADC, by clicking ADC_0.
- Select Drivers:ADC:Window as
Driver from the drop-down menu.
- Select PB1 as analog input
AIN/10 from the SIGNALS menu.
- Ensure all interrupt handlers end up
in driver_isr.c for this training, by un-checking Include harness for IRQ on
conversion...
- Enable the Result Ready Interrupt, by
selecting the RESRDY:Result Ready Interrupt Enable checkbox.
- Ensure the ADC runs when the device
is in Standby Sleep mode, which will be used in the next assignment.
- Ensure the ADC is enabled after initialization, by selecting ENABLE:ADC
Enable.
- Select 8-bit mode as the
RESSEL:ADC Resolution.
- Configure the ADC clock to 625 KHz,
by selecting CLK_PER dividend by 8 from the PRESC:Clock Prescaler
drop-down menu. The main clock runs at 5 MHz, which gives ADC clock at 625 KHz.
- Select VDD as Reference Selection from the drop-down menu.
- Select ADC input pin 10 in the
MUXPOS: Analog Channel Selection Bits field to select the analog input
AIN/10 connected to the ADC.
- Configure the USART module by following
the steps in Figure 7:
Figure 7. USART Configuration
- Open the USART configuration menu, by clicking USART_0.
- Select Driver:USART:Basic as Driver from the drop-down menu.
- Select PB2 as the USART output by selecting it from the TXD drop-down
menu.
- Ensure the output is enabled upon
initialization, by selecting TXEN:Transmitter Enable.
Info: The device will only
send data over USART, so the RXEN:Receiver Enable can remain
unchecked.
- Configure a high baud rate in order
to ensure fast USART data transfer, by setting the Baud Rate to
96000.
Info: Transferring the USART data fast will
enable the device to spend more time in Sleep mode, which will reduce the current
consumption. The Sleep mode will be used in the following assignment.
- Generate the project by clicking
.
- Select the desired path where the project
should be stored as shown in Figure 8 as an example and click OK.
Figure 8. New Atmel Start Project
Result: An Atmel | START project, featuring an ADC and USART driver, has been created in
Atmel Studio.