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參數(shù)資料
| 型號： | DS87C550 |
| 廠商： | Maxim Integrated Products, Inc. |
| 英文描述： | EPROM High-Speed Micro with A/D and PWM(帶 A/D 和 PWM的EPROM/ROM高速微控制器) |
| 中文描述： | 存儲器高速微與A / D及PWM（帶A / D轉(zhuǎn)換和脈寬調(diào)制的存儲器/ ROM的高速微控制器） |
| 文件頁數(shù)： | 26/27頁 |
| 文件大?。?/td> | 119K |
| 代理商： | DS87C550 |
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APPLICATION NOTE 78
030998 26/27
ljmp WDOG_INT
;
cseg at 100h ;Beginning of code segment.
START: MOV TA, #0AAh ;Timed access
MOV TA, #55h
SETB RWT ;Reset watchdog timer
MOV DPTR, #DISPLAY ;Set data pointer to location of display.
CLR F0 ;Clear activity flag
MOV CKCON, #0C1h ;Set watchdog divide ratio to 2**26.
MOV EIE, #10h ;Watchdog Interrupt Enable.
MOV IE, #80h ;Enable all interrupts.
MOV OLD_VAL,P1
MAIN: MOV A, P1 ;Examine external parameter.
CJNE A, OLD_VAL, DIFF ;Begin display update if different.
JMP MAIN
DIFF: MOV CKCON, #0C1h ;Return watchdog divide ratio to slow speed.
MOV PMR, #041h ;Switch back to divide by 4 mode.
MOV OLD_VAL, A ;Save new value.
MOVX @DPTR, A ;Put new value to display.
SETB F0 ;Set flag to indicate we have activity.
SETB EWDI ;Reenable watchdog interrupt (in case device
; was operating in /1024)
JMP MAIN ;End of main program loop
;***************************************************************************
;WDOG_INT – This ISR periodically tests for activity, and if none has been
; detected, drops the device to the next lower clock speed.
; Because the watchdog interval is a function of the clock divisor,
; the watchdog divide ratio is modified in each mode to keep a
; relatively constant interrupt frequency. The following table
; shows the frequencies, assuming a crystal speed of 25 MHz.
; When the device enters /1024 mode, it disables the watchdog
; interrupt, because there is no slower speed to enter.
;
; Clock Mode Divide Ratio WD1 WD0 Watchdog Timeout
; Divide by 4 2**26 1 1 2684 mS
; PMM1 (/64) 2**23 1 0 5368 mS
;***************************************************************************
WDOG_INT: JB F0, DONEWDOG ;If activity has been detected, do not change
; speed.
PUSH ACC ;Save accumulator.
MOV A, PMR ;Check current speed.
JNB ACC.7, D4TO64 ;If CD1 = 0, then mode is /4, switch to /64.
D64TO1024: MOV PMR, #041h ;Speed is now /64. Change to /1024 by first
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| DS87C550-FCL | 制造商:DALLAS 制造商全稱:Dallas Semiconductor 功能描述:EPROM High-Speed Micro with A/D and PWM |
| 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 |
| DS87C550-KCL | 制造商:DALLAS 制造商全稱:Dallas Semiconductor 功能描述:EPROM High-Speed Micro with A/D and PWM |
| DS87C550-QCL | 制造商:DALLAS 制造商全稱:Dallas Semiconductor 功能描述:EPROM High-Speed Micro with A/D and PWM |
| DS87C550-QCL+ | 功能描述:IC MCU EPROM ADC/PWM HS 68-PLCC RoHS:是 類別:集成電路 (IC) >> 嵌入式 - 微控制器， 系列:87C 產(chǎn)品培訓(xùn)模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標(biāo)準(zhǔn)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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