ATTINY40-MMHR Atmel, ATTINY40-MMHR Datasheet - Page 92

• Manufacturer Part Number: ATTINY40-MMHR
• Description: MCU AVR 4KB FLASH 12MHZ 3X3 QFN
• Manufacturer: Atmel
• Series: AVR® ATtinyr

Specifications of ATTINY40-MMHR

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 12MHz
• Connectivity: I²C, SPI
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 18
• Program Memory Size: 4KB (2K x 16)
• Program Memory Type: FLASH
• Ram Size: 256 x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 5.5 V
• Data Converters: A/D 12x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: *
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -

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ATtiny40
then the result of the access outside the interrupt will be corrupted. Therefore, when both the
main code and the interrupt code update the temporary register, the main code must disable the
interrupts during the 16-bit access.
The following code examples show how to do an atomic read of the TCNT1 register contents.
Reading any of the OCR1 register can be done by using the same principle.
Note:
The assembly code example returns the TCNT1H/L value in the r17:r16 register pair.
Assembly Code Example
TIM1_ReadTCNT1:
C Code Example
unsigned int TIM1_ReadTCNT1( void )
{
}
; Save global interrupt flag
in r18,SREG
; Disable interrupts
cli
; Read TCNT1 into r17:r16
in r16,TCNT1L
in r17,TCNT1H
; Restore global interrupt flag
out SREG,r18
ret
unsigned char sreg;
unsigned int i;
/* Save global interrupt flag */
sreg = SREG;
/* Disable interrupts */
_CLI();
/* Read TCNT1 into i */
i = TCNT1L;
i |= ((unsigned int)TCNT1H << 8);
/* Restore global interrupt flag */
SREG = sreg;
return i;
See
“Code Examples” on page
6.
8263A–AVR–08/10