參數(shù)資料
型號: ATmega8535
廠商: Atmel Corp.
元件分類: 8位微控制器
英文描述: -bit AVR Microcontroller with 8K Bytes In- System Programmable Flash
中文描述: 位AVR微控制器具有8K字節(jié)的系統(tǒng)內可編程閃存
文件頁數(shù): 145/152頁
文件大小: 2528K
代理商: ATMEGA8535
90
8151H–AVR–02/11
ATmega128A
13. External Interrupts
The External Interrupts are triggered by the INT7:0 pins. Observe that, if enabled, the interrupts
will trigger even if the INT7:0 pins are configured as outputs. This feature provides a way of gen-
erating a software interrupt. The External Interrupts can be triggered by a falling or rising edge or
a low level. This is set up as indicated in the specification for the External Interrupt Control Reg-
isters – EICRA (INT3:0) and EICRB (INT7:4). When the external interrupt is enabled and is
configured as level triggered, the interrupt will trigger as long as the pin is held low. Note that
recognition of falling or rising edge interrupts on INT7:4 requires the presence of an I/O clock,
described in “Clock Systems and their Distribution” on page 37. Low level interrupts and the
edge interrupt on INT3:0 are detected asynchronously. This implies that these interrupts can be
used for waking the part also from sleep modes other than Idle mode. The I/O clock is halted in
all sleep modes except Idle mode.
Note that if a level triggered interrupt is used for wake-up from Power-down mode, the changed
level must be held for some time to wake up the MCU. This makes the MCU less sensitive to
noise. The changed level is sampled twice by the Watchdog Oscillator clock. The period of the
Watchdog Oscillator is 1 s (nominal) at 5.0V and 25°C. The frequency of the Watchdog Oscilla-
tor is voltage dependent as shown in the “Electrical Characteristics” on page 321. The MCU will
wake up if the input has the required level during this sampling or if it is held until the end of the
start-up time. The start-up time is defined by the SUT fuses as described in “Clock Systems and
their Distribution” on page 37. If the level is sampled twice by the Watchdog Oscillator clock but
disappears before the end of the start-up time, the MCU will still wake up, but no interrupt will be
generated. The required level must be held long enough for the MCU to complete the wake up to
trigger the level interrupt.
13.1
Register Description
13.1.1
EICRA - External Interrupt Control Register A
This Register can not be reached in ATmega103 compatibility mode, but the initial value defines
INT3:0 as low level interrupts, as in ATmega103.
Bits 7:0 – ISC31, ISC30 – ISC00, ISC00: External Interrupt 3 - 0 Sense Control Bits
The External Interrupts 3 - 0 are activated by the external pins INT3:0 if the SREG I-flag and the
corresponding interrupt mask in the EIMSK is set. The level and edges on the external pins that
activate the interrupts are defined in Table 13-1. Edges on INT3:INT0 are registered asynchro-
nously. Pulses on INT3:0 pins wider than the minimum pulse width given in Table 13-2 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. If enabled, a level triggered interrupt will generate an inter-
rupt request as long as the pin is held low. When changing the ISCn bit, an interrupt can occur.
Therefore, it is recommended to first disable INTn by clearing its Interrupt Enable bit in the
EIMSK Register. Then, the ISCn bit can be changed. Finally, the INTn interrupt flag should be
Bit
765
4321
0
ISC31
ISC30
ISC21
ISC20
ISC11
ISC10
ISC01
ISC00
EICRA
Read/Write
R/W
Initial Value
000
0000
0
相關PDF資料
PDF描述
ATMEGA32 8-bit AVR Microcontroller with 32K Bytes In-System Programmable Flash
ATmega64 -bit AVR Microcontroller with 8K Bytes In- System Programmable Flash
ATMEGA8 -bit AVR Microcontroller with 8K Bytes In- System Programmable Flash
ATMEGA8515 -bit AVR Microcontroller with 8K Bytes In- System Programmable Flash
ATMEGA88 -bit AVR Microcontroller with 8K Bytes In- System Programmable Flash
相關代理商/技術參數(shù)
參數(shù)描述
ATmega8535-16AC 功能描述:8位微控制器 -MCU AVR 8K FLASH 512B SRAM 512B EE RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數(shù)據(jù)總線寬度:8 bit 最大時鐘頻率:50 MHz 程序存儲器大小:16 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風格:SMD/SMT
ATMEGA8535-16AI 功能描述:8位微控制器 -MCU AVR 8K FLASH 512B SRAM 512B EE RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數(shù)據(jù)總線寬度:8 bit 最大時鐘頻率:50 MHz 程序存儲器大小:16 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風格:SMD/SMT
ATMEGA8535-16AJ 功能描述:IC MCU AVR 8K 5V 16MHZ 44-TQFP RoHS:是 類別:集成電路 (IC) >> 嵌入式 - 微控制器, 系列:AVR® ATmega 標準包裝:9 系列:87C 核心處理器:8051 芯體尺寸:8-位 速度:40/20MHz 連通性:UART/USART 外圍設備:POR,WDT 輸入/輸出數(shù):32 程序存儲器容量:32KB(32K x 8) 程序存儲器類型:OTP EEPROM 大小:- RAM 容量:256 x 8 電壓 - 電源 (Vcc/Vdd):4.5 V ~ 5.5 V 數(shù)據(jù)轉換器:- 振蕩器型:內部 工作溫度:0°C ~ 70°C 封裝/外殼:40-DIP(0.600",15.24mm) 包裝:管件
ATmega8535-16AU 功能描述:8位微控制器 -MCU 8kB Flash 0.5kB EEPROM 32 I/O Pins RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數(shù)據(jù)總線寬度:8 bit 最大時鐘頻率:50 MHz 程序存儲器大小:16 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風格:SMD/SMT
ATMEGA8535-16AUR 功能描述:8位微控制器 -MCU AVR 8K FLSH 544B SRAM 512B EE-16MHz RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數(shù)據(jù)總線寬度:8 bit 最大時鐘頻率:50 MHz 程序存儲器大小:16 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風格:SMD/SMT