ATtiny24A Atmel Corporation, ATtiny24A Datasheet - Page 50

• Manufacturer Part Number: ATtiny24A
• Manufacturer: Atmel Corporation

Specifications of ATtiny24A

• Flash (kbytes): 2 Kbytes
• Pin Count: 14
• Max. Operating Frequency: 20 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 4
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 12
• Ext Interrupts: 12
• Usb Speed: No
• Usb Interface: No
• Spi: 1
• Twi (i2c): 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 8
• Adc Resolution (bits): 10
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: Yes
• Crypto Engine: No
• Sram (kbytes): 0.12
• Eeprom (bytes): 128
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: Yes
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 1.8 to 5.5
• Operating Voltage (vcc): 1.8 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 2
• Output Compare Channels: 4
• Input Capture Channels: 1
• Pwm Channels: 4
• 32khz Rtc: No
• Calibrated Rc Oscillator: Yes

9.3
9.3.1
9.3.2
50
Register Description
ATtiny24A/44A/84A
MCUCR – MCU Control Register
GIMSK – General Interrupt Mask Register
The External Interrupt Control Register A contains control bits for interrupt sense control.
• Bits 1:0 – ISC0[1:0]: Interrupt Sense Control 0 Bit 1 and Bit 0
The External Interrupt 0 is activated by the external pin INT0 if the SREG I-flag and the corre-
sponding interrupt mask are set. The level and edges on the external INT0 pin that activate the
interrupt are defined in
If edge or toggle interrupt is selected, pulses that last longer than one clock period will generate
an interrupt. Shorter pulses are not guaranteed to generate an interrupt. If low level interrupt is
selected, the low level must be held until the completion of the currently executing instruction to
generate an interrupt.
Table 9-2.
• Bits 7, 3:0 – Res: Reserved Bits
These bits are reserved in the ATtiny24A/44A and will always read as zero.
• Bit 6 – INT0: External Interrupt Request 0 Enable
When the INT0 bit is set (one) and the I-bit in the Status Register (SREG) is set (one), the exter-
nal pin interrupt is enabled. The Interrupt Sense Control bits (ISC01 and ISC00) in the External
Interrupt Control Register A (EICRA) define whether the external interrupt is activated on rising
and/or falling edge of the INT0 pin or level sensed. Activity on the pin will cause an interrupt
request even if INT0 is configured as an output. The corresponding interrupt of External Interrupt
Request 0 is executed from the INT0 Interrupt Vector.
• Bit 5 – PCIE1: Pin Change Interrupt Enable 1
When the PCIE1 bit is set (one) and the I-bit in the Status Register (SREG) is set (one), pin
change interrupt 1 is enabled. Any change on any enabled PCINT[11:8] pin will cause an inter-
rupt. The corresponding interrupt of Pin Change Interrupt Request is executed from the PCI1
Interrupt Vector. PCINT[11:8] pins are enabled individually by the PCMSK1 Register.
Bit
0x35 (0x55)
Read/Write
Initial Value
Bit
0x3B (0x5B)
Read/Write
Initial Value
ISC01
0
0
1
1
Interrupt 0 Sense Control
ISC00
BODS
R/W
7
0
R
7
–
0
0
1
0
1
Table
PUD
R/W
INT0
R/W
Description
The low level of INT0 generates an interrupt request.
Any logical change on INT0 generates an interrupt request.
The falling edge of INT0 generates an interrupt request.
The rising edge of INT0 generates an interrupt request.
6
0
6
0
9-2. The value on the INT0 pin is sampled before detecting edges.
PCIE1
R/W
R/W
SE
5
0
5
0
PCIE0
SM1
R/W1
R/W
4
0
4
0
SM0
R/W
3
0
R
3
–
0
BODSE
R/W
2
0
R
2
–
0
ISC01
R/W
1
0
R
1
–
0
ISC00
R/W
0
0
R
0
–
0
8183D–AVR–04/11
MCUCR
GIMSK