參數(shù)資料
型號(hào)： DS87C530-QNL
英文描述： EPROM MICRO WITH REAL TIME CLOCK
中文描述： 微型存儲(chǔ)器與實(shí)時(shí)時(shí)鐘
文件頁(yè)數(shù)： 22/40頁(yè)
文件大小： 435K
代理商： DS87C530-QNL
DS87C530
022197 22/40
WATCHDOG TIME–OUT VALUES
Table 8
INTERRUPT
WD1
0
WD0
0
TIME–OUT
2
17
clocks
2
20
clocks
2
23
clocks
2
26
clocks
TIME (33 MHz)
3.9718 ms
RESET TIME–OUT
2
17
+ 512 clocks
2
20
+ 512 clocks
2
23
+ 512 clocks
2
26
+ 512 clocks
TIME (33 MHz)
3.9874 ms
0
1
31.77 ms
31.79 ms
1
0
254.20 ms
254.21 ms
1
1
2033.60 ms
2033.62 ms
As shown above, the Watchdog Timer uses the crystal
frequency as a time base. A user selects one of four
counter values to determine the time–out. These clock
counter lengths are 2
17
= 131,072 clocks; 2
20
=
1,048,576; 2
23
= 8,388,608 clocks; and 2
26
=
67,108,864 clocks. The times shown in Table 8 above
are with a 33 MHz crystal frequency. Once the counter
chain has completed a full interrupt count, hardware 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 five 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 time–out. Both of
these bits are protected by Timed Access discussed
below. As mentioned previously, WD1 and 0 (CKCON .7
and 6) select the time–out. Finally, the user can enable
the Watchdog Interrupt using EWDI (EIE.4). The Spe-
cial Function Register map is shown above.
INTERRUPTS
The DS87C530 provides 14 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.
INTERRUPT SOURCES AND PRIORITIES
Table 9
NAME
PFI
INT0
TF0
INT1
TF1
SCON0
TF2
SCON1
INT2
INT3
INT4
INT5
WDTI
RTCI
DESCRIPTION
Power Fail Interrupt
External Interrupt 0
Timer 0
External Interrupt 1
Timer 1
TI0 or RI0 from serial port 0
Timer 2
TI1 or RI1 from serial port 1
External Interrupt 2
External Interrupt 3
External Interrupt 4
External Interrupt 5
Watchdog Time–Out Interrupt
Real Time Clock Interrupt
VECTOR
33h
03h
0Bh
13h
1Bh
23h
2Bh
3Bh
43h
4Bh
53h
5Bh
63h
6Bh
NATURAL
PRIORITY
1
2
3
4
5
6
7
8
9
10
11
12
13
14
8051/DALLAS
DALLAS
8051
8051
8051
8051
8051
8051
DALLAS
DALLAS
DALLAS
DALLAS
DALLAS
DALLAS
DALLAS
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參數(shù)描述
DS87C530-QNL+ 功能描述:8位微控制器 -MCU EPROM MCU w/RTC 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(shí)鐘頻率:50 MHz 程序存儲(chǔ)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(fēng)格:SMD/SMT
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DS87C550-FNL 制造商:DALLAS 制造商全稱:Dallas Semiconductor 功能描述:EPROM High-Speed Micro with A/D and PWM
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