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參數資料
型號: W79E802A
廠商: WINBOND ELECTRONICS CORP
元件分類: 8位微控制器
英文描述: 8-BIT MICROCONTROLLER
中文描述: 8位微控制器
文件頁數: 62/115頁
文件大小: 1456K
代理商: W79E802A
W79E804A/803A/802A
- 62 -
12.2 Priority Level Structure
The W79E804 series uses a four priority level interrupt structure (highest, high, low and lowest) and
supports up to 12 interrupt sources. The interrupt sources can be individually set to either high or low
levels. Naturally, a higher priority interrupt cannot be interrupted by a lower priority interrupt. However
there exists a pre-defined hierarchy amongst the interrupts themselves. This hierarchy comes into play
when the interrupt controller has to resolve simultaneous requests having the same priority level. This
hierarchy is defined as table below. This allows great flexibility in controlling and handling many
interrupt sources.
PRIORITY BITS
IPXH
IPX
INTERRUPT PRIORITY LEVEL
0
0
1
1
0
1
0
1
Level 0 (lowest priority)
Level 1
Level 2
Level 3 (highest priority)
Table
12-2: Four-level interrupt priority
Each interrupt source can be individually programmed to one of four priority levels by setting or
clearing bits in the IP0, IP0H, IP1, and IP1H registers. An interrupt service routine in progress can be
interrupted by a higher priority interrupt, but not by another interrupt of the same or lower priority. The
highest priority interrupt service cannot be interrupted by any other interrupt source. So, if two
requests of different priority levels are received simultaneously, the request of higher priority level is
serviced.
If requests of the same priority level are received simultaneously, an internal polling sequence
determines which request is serviced. This is called the arbitration ranking. Note that the arbitration
ranking is only used to resolve simultaneous requests of the same priority level.
As below Table summarizes the interrupt sources, flag bits, vector addresses, enable bits, priority bits,
arbitration ranking, and whether each interrupt may wake up the CPU from Power Down mode.
SOURCE
FLAG
VECTOR
ADDRESS
INTERRUPT
ENABLE
BITS
INTERRUPT
PRIORITY
FLAG
CLEARED BY
ARBITRATION
RANKING
POWER
DOWN
WAKEUP
External
Interrupt 0
IE0
0003H
EX0
(IE0.0)
IP0H.0,
IP0.0
Hardware,
Follow the
inverse of
pin
1(highest)
Yes
Brownout
Detect
BOF
002BH
EBO (IE.5)
IP0H.5,
IP0.5
Software
2
Yes
Watchdog
Timer
WDIF
0053H
EWDI
(EIE.4)
IP1H.4,
IP1.4
Software
3
Yes
(1)
相關PDF資料
PDF描述
W79E802ADG 8-BIT MICROCONTROLLER
W79E802ASG 8-BIT MICROCONTROLLER
W79E803 8-BIT MICROCONTROLLER
W79E803A 8-BIT MICROCONTROLLER
W79E803ADG 8-BIT MICROCONTROLLER
相關代理商/技術參數
參數描述
W79E802ADG 制造商:WINBOND 制造商全稱:Winbond 功能描述:8-BIT MICROCONTROLLER
W79E802ASG 制造商:WINBOND 制造商全稱:Winbond 功能描述:8-BIT MICROCONTROLLER
W79E803 制造商:WINBOND 制造商全稱:Winbond 功能描述:8-BIT MICROCONTROLLER
W79E803A 制造商:WINBOND 制造商全稱:Winbond 功能描述:8-BIT MICROCONTROLLER
W79E803ADG 制造商:WINBOND 制造商全稱:Winbond 功能描述:8-BIT MICROCONTROLLER