View source for Custom Interrupts - AVR

<sidebar>Sidebar: What Is an Interrupt?</sidebar>
<font style="color:#FF0000"> '''Target AVR Processor''' ( ATMEGA8, 16, 32 )

'''(Note: For other AVR devices you may have to refer to the device datasheet to obtain the correct code)''' </font>


==USART Receive==

[[File:Gen_Customer_Interrupts_AVR_USART.png|right]]

The Flowcode RS232 component can be used to set the Baud rate and configure the mode of operation, and the ReceiveRS232Char function can be used in the handler macro to read the data (clearing the interrupt).


'''Enable code:'''

<span style="color:#000080"> UCSRB |= ((1 << RXCIE) | (1 << RXEN)); // enable USART receiver and receive interrupts </span>


'''Disable code:'''

<span style="color:#000080"> UCSRB &= ~(1 << RXCIE); // disable USART receive interrupts </span>


'''Handler code:'''

<font style="color:#000080"> ISR(USART_RXC_vect) // USART receive vector

{

FCM_%n();

}</font>








==Analogue Comparator==

[[File:Gen_Custom_Interrupts_AVR_COMPARITOR.png|right]]


'''Enable code:'''

<font style="color:#000080"> SFIOR &= ~(1 << ACME); // disable multiplexer input

ACSR |= (1 << ACIE); // enable comparator interrupts - interrupt when comparator output toggles </font>


'''Disable code:''

<span style="color:#000080"> ACSR &= ~(1 << ACIE); // disable comparator interrupts </span>


'''Handler code:'''

<font style="color:#000080"> ISR(ANA_COMP_vect) // analogue comparator interrupt vector

{

FCM_%n();

}</font>


The state of the comparator input can be read into a Flowcode variable 'compstate' with the following C code line:


<span style="color:#000080"> FCV_COMPSTATE = ACSR & (1 << ACO); </span>




==Timer1 Rollover==

[[File:Gen_Custom_Interrupts_AVR_TIMER1.png|right]]


'''Enable code:'''

<font style="color:#000080"> TCCR1B = 0x45; // positive edge trigger with no noise canceler, prescaler = /1024

TIMSK |= (1 << TICIE1); // enable input capture interrupts </font>


'''Disable code:'''

<span style="color:#000080"> TIMSK &= ~(1 << TICIE1); // disable input capture interrupts </span>


'''Handler code:'''

<font style="color:#000080"> ISR(TIMER1_CAPT_vect) // input capture vector

{

FCM_%n();

}</font>


The captured 16-bit count value can be read into a Flowcode variable 'captval' with the following C code line:


<span style="color:#000080"> FCV_CAPTVAL = ICR1; </span>

{| width="auto"
|<pre>** captval must be declared as an integer variable **</pre>
|}