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參數(shù)資料
| 型號： | DS89C420-ECL |
| 英文描述： | Ultra-High-Speed Microcontroller |
| 中文描述： | 超高速微控制器 |
| 文件頁數(shù)： | 39/59頁 |
| 文件大?。?/td> | 539K |
| 代理商： | DS89C420-ECL |
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DS89C420
39 of 59
When the DS89C420 enters stop mode, the bandgap, reset comparator, and power-fail interrupt
comparator are automatically disabled to conserve power, if the BGS (EXIF.0) bit is set to a logic 0. This
is the lowest power mode. If BGS is set to a logic 1, the bandgap reference, reset comparator, and the
power-fail comparator are powered up, although in a reduced fashion, while in stop mode.
Watchdog Timer
The watchdog timer functions as the source of both the watchdog interrupt and the watchdog reset. When
the clock divider is set to 10b, the interrupt timeout has a default divide ratio of 2
17
of the crystal oscillator
clock, with the watchdog reset set to timeout 512 system clock cycles later. This results in a 33MHz
crystal oscillator producing an interrupt timeout every 3.9718ms, followed 15.5μs later by a watchdog
reset. The watchdog timer is reset to the default divide ratio following any reset. Using the WD0 and
WD1 bits in the clock control (CKCON.6 and 7) register, other divide ratios can be selected for longer
watchdog interrupt periods. Table 14 summarizes the watchdog bit settings and the timeout values.
Note:
All watchdog-timer reset timeouts follow the programmed interrupt timeouts by 512 system clock
cycles, which equates to varying numbers of oscillator cycles depending on the clock-divide (CD1:0) and
crystal multiplier settings.
Table 14. Watchdog Timeout Value (in Number of Oscillator Clocks)
WATCHDOG INTERRUPT TIMEOUT
WATCHDOG RESET TIMEOUT
4X
/
X
2
CD1:0
WD1:0 = 00
2
15
2
16
2
17
2
17
WD1:0 = 01 WD1:0 = 10 WD1:0 = 11
2
18
2
21
2
19
2
22
2
20
2
23
2
20
2
23
WD1:0 = 00
2
15
+ 128
2
16
+ 256
2
17
+ 512
2
17
+ 512
WD1:0 = 01
2
18
+ 128
2
19
+ 256
2
20
+ 512
2
20
+ 512
WD1:0 = 10
2
21
+ 128
2
22
+ 256
2
23
+ 512
2
23
+ 512
WD1:0 = 11
2
24
+ 128
2
25
+ 256
2
26
+ 512
2
26
+ 512
1
0
x
x
00
00
01
10
2
24
2
25
2
26
2
26
x
11
2
27
2
30
2
33
2
36
2
27
+ 524,288
2
30
+ 524,288
2
33
+ 524,288
2
36
+ 524,288
A watchdog control (WDCON) SFR is used for programming the functions. EWT (WDCON.1) is the
enable for the watchdog-timer reset function and RWT (WDCON.0) is the bit used to restart the
watchdog timer. Setting the RWT bit restarts the timer for another full interval. If the watchdog timer
reset function is masked by the EWT bit and no resets are issued to the timer through the RWT bit, the
watchdog timer generates interrupt timeouts at a rate determined by the programmed divide ratio. WDIF
(WDCON.3) is the interrupt flag set at timer termination and WTRF (WDCON.2) is the reset flag set
following a watchdog reset timeout. The watchdog interrupt is enabled by the EWDI bit (EIE.4) when it
is set to 1. The watchdog timer reset and interrupt timeouts are measured by counting system clock
cycles.
An independent watchdog timer functions as the crystal startup counter to count 65,536 crystal clock
cycles before allowing the crystal oscillator to function as the system clock. This warmup time is verified
by the watchdog timer following each power-up as well as each time the crystal is restarted following a
stop mode. The watchdog is also used to establish a startup time whenever the CTM in the PMR register
is set to enable the crystal multiplier (4X
/
X
2
).
One of the applications of the watchdog timer is for the watchdog to wake up the system from idle mode.
The watchdog interrupt can be programmed to allow a system to wake up periodically to sample the
external world.
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| DS89C420-ECS | 功能描述:IC MCU 50MHZ ULTRA HS 44-TQFP RoHS:否 類別:集成電路 (IC) >> 嵌入式 - 微控制器， 系列:89C 產(chǎn)品培訓(xùn)模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標準包裝:260 系列:73S12xx 核心處理器:80515 芯體尺寸:8-位 速度:24MHz 連通性:I²C，智能卡，UART/USART，USB 外圍設(shè)備:LED，POR，WDT 輸入/輸出數(shù):9 程序存儲器容量:64KB（64K x 8） 程序存儲器類型:閃存 EEPROM 大小:- RAM 容量:2K x 8 電壓 - 電源 (Vcc/Vdd):2.7 V ~ 5.5 V 數(shù)據(jù)轉(zhuǎn)換器:- 振蕩器型:內(nèi)部 工作溫度:-40°C ~ 85°C 封裝/外殼:68-VFQFN 裸露焊盤 包裝:管件 |
| DS89C420-ENG | 功能描述:IC MCU ULTRA 25MHZ HP 44-TQFP RoHS:否 類別:集成電路 (IC) >> 嵌入式 - 微控制器， 系列:89C 產(chǎn)品培訓(xùn)模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標準包裝:260 系列:73S12xx 核心處理器:80515 芯體尺寸:8-位 速度:24MHz 連通性:I²C，智能卡，UART/USART，USB 外圍設(shè)備:LED，POR，WDT 輸入/輸出數(shù):9 程序存儲器容量:64KB（64K x 8） 程序存儲器類型:閃存 EEPROM 大小:- RAM 容量:2K x 8 電壓 - 電源 (Vcc/Vdd):2.7 V ~ 5.5 V 數(shù)據(jù)轉(zhuǎn)換器:- 振蕩器型:內(nèi)部 工作溫度:-40°C ~ 85°C 封裝/外殼:68-VFQFN 裸露焊盤 包裝:管件 |
| DS89C420-ENL | 制造商:MAXIM 制造商全稱:Maxim Integrated Products 功能描述:Ultra-High-Speed Microcontroller |
| DS89C420-MCL | 功能描述:IC MCU ULTRA 33MHZ HP 40-DIP RoHS:否 類別:集成電路 (IC) >> 嵌入式 - 微控制器， 系列:89C 產(chǎn)品培訓(xùn)模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標準包裝:260 系列:73S12xx 核心處理器:80515 芯體尺寸:8-位 速度:24MHz 連通性:I²C，智能卡，UART/USART，USB 外圍設(shè)備:LED，POR，WDT 輸入/輸出數(shù):9 程序存儲器容量:64KB（64K x 8） 程序存儲器類型:閃存 EEPROM 大小:- RAM 容量:2K x 8 電壓 - 電源 (Vcc/Vdd):2.7 V ~ 5.5 V 數(shù)據(jù)轉(zhuǎn)換器:- 振蕩器型:內(nèi)部 工作溫度:-40°C ~ 85°C 封裝/外殼:68-VFQFN 裸露焊盤 包裝:管件 |
| DS89C420-MCS | 功能描述:IC MCU 50MHZ ULTRA HS 40-DIP RoHS:否 類別:集成電路 (IC) >> 嵌入式 - 微控制器， 系列:89C 產(chǎn)品培訓(xùn)模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標準包裝:260 系列:73S12xx 核心處理器:80515 芯體尺寸:8-位 速度:24MHz 連通性:I²C，智能卡，UART/USART，USB 外圍設(shè)備:LED，POR，WDT 輸入/輸出數(shù):9 程序存儲器容量:64KB（64K x 8） 程序存儲器類型:閃存 EEPROM 大小:- RAM 容量:2K x 8 電壓 - 電源 (Vcc/Vdd):2.7 V ~ 5.5 V 數(shù)據(jù)轉(zhuǎn)換器:- 振蕩器型:內(nèi)部 工作溫度:-40°C ~ 85°C 封裝/外殼:68-VFQFN 裸露焊盤 包裝:管件 |
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