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參數(shù)資料
| 型號： | DS87C520 |
| 英文描述： | EPROM/ROM High-Speed Micro |
| 中文描述： | EPROM/ROM高速微控制器 |
| 文件頁數(shù)： | 24/45頁 |
| 文件大?。?/td> | 1415K |
| 代理商： | DS87C520 |
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DS87C520/DS83C520 EPROM/ROM High-Speed Microcontrollers
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will set an interrupt flag. Regardless of whether the user enables this interrupt, there are then 512 clocks
left until the reset flag is set. Software can enable the interrupt and reset individually. Note that the
Watchdog is a free running timer and does not require an enable.
There are 5 control bits in special function registers that affect the Watchdog Timer and two status flags
that report to the user. WDIF (WDCON.3) is the interrupt flag that is set at timer termination when there
are 512 clocks remaining until the reset flag is set. WTRF (WDCON.2) is the flag that is set when the
timer has completely timed out. This flag is normally associated with a CPU reset and allows software to
determine the reset source.
EWT (WDCON.1) is the enable for the Watchdog timer reset function. RWT (WDCON.0) is the bit that
software uses to restart the Watchdog Timer. Setting this bit restarts the timer for another full interval.
Application software must set this bit before the timeout. Both of these bits are protected by Timed
Access. As mentioned previously, WD1 and 0 (CKCON .7 and 6) select the timeout. The Reset
Watchdog Timer bit (WDCON.0) should be asserted prior to modifying the Watchdog Timer Mode
Select bits (WD1, WD0) to avoid corruption of the watchdog count. Finally, the user can enable the
Watchdog Interrupt using EWDI (EIE.4). The Special Function Register map is shown above.
INTERRUPTS
The DS87C520/DS83C520 provide 13 interrupt sources with three priority levels. The Power-Fail
Interrupt (PFI) has the highest priority. Software can assign high or low priority to other sources. All
interrupts that are new to the 8051 family, except for the PFI, have a lower natural priority than the
originals.
Table 8. Interrupt Sources and Priorities
NAME
FUNCTION
VECTOR
NATURAL
PRIORITY
1
8051/DALLAS
PFI
Power-Fail Interrupt
33h
DALLAS
INT0
TF0
External Interrupt 0
03h
2
8051
Timer 0
0Bh
3
8051
INT1
TF1
SCON0
TF2
SCON1
INT2
External Interrupt 1
13h
4
8051
Timer 1
TI0 or RI0 from serial port 0
Timer 2
TI1 or RI1 from serial port 1
External Interrupt 2
1Bh
23h
2Bh
3Bh
43h
5
6
7
8
9
8051
8051
8051
DALLAS
DALLAS
INT3
INT4
External Interrupt 3
4Bh
10
DALLAS
External Interrupt 4
53h
11
DALLAS
INT5
WDTI
External Interrupt 5
5Bh
12
DALLAS
Watchdog Timeout Interrupt
63h
13
DALLAS
相關PDF資料 |
PDF描述 |
|---|---|
| DS87C520-ECL | EPROM/ROM High-Speed Micro |
| DS87C520-ENL | EPROM/ROM High-Speed Micro |
| DS87C520-MCL | EPROM/ROM High-Speed Micro |
| DS87C520-MNL | EPROM/ROM High-Speed Micro |
| DS87C520-QCL | EPROM/ROM High-Speed Micro |
相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| DS87C520_1 | 制造商:DALLAS 制造商全稱:Dallas Semiconductor 功能描述:EPROM/ROM High-Speed Micro |
| DS87C520+ECL | 制造商:Maxim Integrated Products 功能描述:MICRO OTP HI SPD 44TQFP 33MHZ PB-FR - Trays |
| DS87C520+MCL | 制造商:Maxim Integrated Products 功能描述:MICRO OTP HI SPD 40PDIP 33MHZ PB-FR - Rail/Tube 制造商:Maxim Integrated Products 功能描述:IC 8BIT CPU CMOS 87C520 DIP40 |
| DS87C520+MNL | 制造商:Maxim Integrated Products 功能描述:MICRO HI SPD 40PDIP 33MHZ IND PB-FR - Rail/Tube |
| DS87C520+QCL | 制造商:Maxim Integrated Products 功能描述:MCU 8BIT CISC 16KB EPROM 5V 44PLCC - Rail/Tube |
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