ATTINY261A-MU Atmel, ATTINY261A-MU Datasheet - Page 107

• Manufacturer Part Number: ATTINY261A-MU
• Description: NO NEW DESIGNS, USE TINY261A-XU - 20MHZ, QFN/MLF,IND TEMP, G
• Manufacturer: Atmel

12.11.2
8197B–AVR–01/10
Code Examples
The following code examples show how to access the 10-bit timer registers assuming that no
interrupts updates the TC1H register. The same principle can be used directly for accessing the
OCR1A/B/C/D registers.
Note:
The assembly code example returns the TCNT1 value in the r17:r16 register pair.
It is important to notice that accessing 10-bit registers are atomic operations. If an interrupt
occurs between the two instructions accessing the 10-bit register, and the interrupt code
updates the TC1H register by accessing the same or any other of the 10-bit timer registers, then
the result of the access outside the interrupt will be corrupted. Therefore, when both the main
code and the interrupt code update the TC1H register, the main code must disable the interrupts
during the 16-bit access.
Assembly Code Example
C Code Example
unsigned int i;
...
/* Set TCNT1 to 0x01FF */
TC1H = 0x01;
TCNT1 = 0xFF;
/* Read TCNT1 into i */
i = TCNT1;
i |= ((unsigned int)TC1H << 8);
...
...
; Set TCNT1 to 0x01FF
ldi r17,0x01
ldi r16,0xFF
out TC1H,r17
out TCNT1,r16
; Read TCNT1 into r17:r16
in r16,TCNT1
in r17,TC1H
...
See
“Code Examples” on page
6.
107