参数资料
型号: M38869FFAHP
元件分类: 微控制器/微处理器
英文描述: 8-BIT, FLASH, 5 MHz, MICROCONTROLLER, PQFP80
封装: 12 X 12 MM, 0.50 MM PITCH, PLASTIC, LQFP-80
文件页数: 68/113页
文件大小: 1871K
代理商: M38869FFAHP
55
3886 Group
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
MITSUBISHI MICROCOMPUTERS
WATCHDOG TIMER
The watchdog timer gives a mean of returning to the reset status
when a program cannot run on a normal loop (for example, be-
cause of a software run-away). The watchdog timer consists of an
8-bit watchdog timer L and an 8-bit watchdog timer H.
Standard Operation of Watchdog Timer
When any data is not written into the watchdog timer control reg-
ister (address 001E16) after resetting, the watchdog timer is in the
stop state. The watchdog timer starts to count down by writing an
optional value into the watchdog timer control register (address
001E16) and an internal reset occurs at an underflow of the watch-
dog timer H.
Accordingly, programming is usually performed so that writing to
the watchdog timer control register (address 001E16) may be
started before an underflow. When the watchdog timer control reg-
ister (address 001E16) is read, the values of the high-order 6 bits
of the watchdog timer H, STP instruction disable bit, and watch-
dog timer H count source selection bit are read.
Initial Value of Watchdog Timer
At reset or writing to the watchdog timer control register (address
001E16), each watchdog timer H and L is set to “FF16.”
Fig. 54 Structure of Watchdog timer control register
qWatchdog timer H count source selection bit operation
Bit 7 of the watchdog timer control register (address 001E16) per-
mits selecting a watchdog timer H count source. When this bit is
set to “0”, the count source becomes the underflow signal of
watchdog timer L. The detection time is set to f(XIN)=131.072 ms
at 8 MHz frequency and f(XCIN)=32.768 s at 32 kHz frequency.
When this bit is set to “1”, the count source becomes the signal
divided by 16 for f(XIN) (or f(XCIN)). The detection time in this case
is set to f(XIN)= 512
s at 8 MHz frequency and f(XCIN)=128 ms at
32 kHz frequency. This bit is cleared to “0” after resetting.
qOperation of STP instruction disable bit
Bit 6 of the watchdog timer control register (address 001E16) per-
mits disabling the STP instruction when the watchdog timer is in
operation.
When this bit is “0”, the STP instruction is enabled.
When this bit is “1”, the STP instruction is disabled.
Once the STP instruction is executed, an internal reset occurs.
When this bit is set to “1”, it cannot be rewritten to “0” by program.
This bit is cleared to “0” after resetting.
Fig. 53 Block diagram of Watchdog timer
XIN
Data bus
XCIN
“10”
“00”
“01”
Main clock division
ratio selection bits
(Note)
“0”
“1”
1/16
Watchdog timer H count
source selection bit
Reset
circuit
STP instruction disable bit
Watchdog timer H (8)
“FF16” is set when
watchdog timer
control register is
written to.
Internal reset
RESET
Watchdog timer L (8)
Note: Either high-speed, middle-speed or low-speed mode is selected by bits 7 and 6 of the CPU mode register.
STP instruction
“FF16” is set when
watchdog timer
control register is
written to.
b0
STP instruction disable bit
0: STP instruction enabled
1: STP instruction disabled
Watchdog timer H count source selection bit
0: Watchdog timer L underflow
1: f(XIN)/16 or f(XCIN)/16
Watchdog timer H (for read-out of high-order 6 bit)
Watchdog timer control register
(WDTCON : address 001E16)
b7
相关PDF资料
PDF描述
MSP430F5419AIPZ 16-BIT, FLASH, 25 MHz, RISC MICROCONTROLLER, PQFP100
M30221M4-XXXFP 16-BIT, MROM, 10 MHz, MICROCONTROLLER, PQFP120
M38207M8-XXXHP 8-BIT, MROM, 4 MHz, MICROCONTROLLER, PQFP80
M38254M4DXXXFP 8-BIT, MROM, 4 MHz, MICROCONTROLLER, PQFP100
MB90341EPFV MICROCONTROLLER, PQFP100
相关代理商/技术参数
参数描述
M38869FFAHP#UU 功能描述:IC 740/3886 MCU FLASH 80LQFP RoHS:是 类别:集成电路 (IC) >> 嵌入式 - 微控制器, 系列:740/38000 产品培训模块:CAN Basics Part-1 CAN Basics Part-2 Electromagnetic Noise Reduction Techniques Part 1 M16C Product Overview Part 1 M16C Product Overview Part 2 标准包装:1 系列:M16C™ M32C/80/87 核心处理器:M32C/80 芯体尺寸:16/32-位 速度:32MHz 连通性:EBI/EMI,I²C,IEBus,IrDA,SIO,UART/USART 外围设备:DMA,POR,PWM,WDT 输入/输出数:121 程序存储器容量:384KB(384K x 8) 程序存储器类型:闪存 EEPROM 大小:- RAM 容量:24K x 8 电压 - 电源 (Vcc/Vdd):3 V ~ 5.5 V 数据转换器:A/D 34x10b,D/A 2x8b 振荡器型:内部 工作温度:-20°C ~ 85°C 封装/外壳:144-LQFP 包装:托盘 产品目录页面:749 (CN2011-ZH PDF) 配用:R0K330879S001BE-ND - KIT DEV RSK M32C/87
M38869FF-XXXHP 制造商:RENESAS 制造商全称:Renesas Technology Corp 功能描述:SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
M38869M1-XXXHP 制造商:RENESAS 制造商全称:Renesas Technology Corp 功能描述:SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
M38869M2-XXXHP 制造商:RENESAS 制造商全称:Renesas Technology Corp 功能描述:SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
M38869M3-XXXHP 制造商:RENESAS 制造商全称:Renesas Technology Corp 功能描述:SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER