- 您現(xiàn)在的位置：買賣IC網 > PDF目錄367743 > P89LPC938FA (NXP SEMICONDUCTORS) 8-bit microcontroller with accelerated two-clock 80C51 core 8 kB 3 V byte-erasable Flash with 10-bit A/D converter PDF資料下載
參數(shù)資料
| 型號： | P89LPC938FA |
| 廠商： | NXP SEMICONDUCTORS |
| 元件分類： | 微控制器/微處理器 |
| 英文描述： | 8-bit microcontroller with accelerated two-clock 80C51 core 8 kB 3 V byte-erasable Flash with 10-bit A/D converter |
| 中文描述： | 8-BIT, FLASH, 18 MHz, MICROCONTROLLER, PQCC28 |
| 封裝： | PLASTIC, MS-018, SOT-261-2, LCC-28 |
| 文件頁數(shù)： | 42/68頁 |
| 文件大?。?/td> | 318K |
| 代理商： | P89LPC938FA |
第1頁第2頁第3頁第4頁第5頁第6頁第7頁第8頁第9頁第10頁第11頁第12頁第13頁第14頁第15頁第16頁第17頁第18頁第19頁第20頁第21頁第22頁第23頁第24頁第25頁第26頁第27頁第28頁第29頁第30頁第31頁第32頁第33頁第34頁第35頁第36頁第37頁第38頁第39頁第40頁第41頁當前第42頁第43頁第44頁第45頁第46頁第47頁第48頁第49頁第50頁第51頁第52頁第53頁第54頁第55頁第56頁第57頁第58頁第59頁第60頁第61頁第62頁第63頁第64頁第65頁第66頁第67頁第68頁
9397 750 14051
Koninklijke Philips Electronics N.V. 2005. All rights reserved.
Product data sheet
Rev. 01 — 25 February 2005
42 of 68
Philips Semiconductors
P89LPC938
8-bit microcontroller with 10-bit A/D converter
7.25 Watchdog timer
The watchdog timer causes a system reset when it underflows as a result of a failure to
feed the timer prior to the timer reaching its terminal count. It consists of a programmable
12-bit prescaler, and an 8-bit down counter. The down counter is decremented by a tap
taken from the prescaler. The clock source for the prescaler is either the PCLK or the
nominal 400 kHz Watchdog oscillator. The watchdog timer can only be reset by a
power-on reset. When the watchdog feature is disabled, it can be used as an interval timer
and may generate an interrupt.
Figure 20
shows the watchdog timer in Watchdog mode.
Feeding the watchdog requires a two-byte sequence. If PCLK is selected as the watchdog
clock and the CPU is powered-down, the watchdog is disabled. The watchdog timer has a
time-out period that ranges from a few
μ
s to a few seconds. Please refer to the
P89LPC938 User’s Manualfor more details.
7.26 Additional features
7.26.1
Software reset
The SRST bit in AUXR1 gives software the opportunity to reset the processor completely,
as if an external reset or watchdog reset had occurred. Care should be taken when writing
to AUXR1 to avoid accidental software resets.
7.26.2
Dual data pointers
The dual Data Pointers (DPTR) provides two different Data Pointers to specify the address
used with certain instructions. The DPS bit in the AUXR1 register selects one of the two
Data Pointers. Bit 2 of AUXR1 is permanently wired as a logic 0 so that the DPS bit may
be toggled (thereby switching Data Pointers) simply by incrementing the AUXR1 register,
without the possibility of inadvertently altering other bits in the register.
(1) Watchdog reset can also be caused by an invalid feed sequence, or by writing to WDCON not immediately followed by a
feed sequence.
Fig 20. Watchdog timer in Watchdog mode (WDTE = ‘1’).
PRE2
PRE1
PRE0
-
-
WDRUN
WDTOF
WDCLK
WDCON (A7H)
SHADOW REGISTER
PRESCALER
002aaa905
8-BIT DOWN
COUNTER
WDL (C1H)
watchdog
oscillator
PCLK
÷
32
MOV WFEED1, #0A5H
MOV WFEED2, #05AH
reset
(1)
相關PDF資料 |
PDF描述 |
|---|---|
| P89LV51RB2BBC | 8-bit 80C51 3 V low power 16/32/64 kB Flash microcontroller with 1 kB RAM |
| P89LV51RB2 | 8-bit 80C51 3 V low power 16/32/64 kB Flash microcontroller with 1 kB RAM |
| P89LV51RB2BA | 8-bit 80C51 3 V low power 16/32/64 kB Flash microcontroller with 1 kB RAM |
| P89LV51RD2BN | 8-bit 80C51 3 V low power 16/32/64 kB Flash microcontroller with 1 kB RAM |
| P89LV51RD2 | 8-bit 80C51 3 V low power 64 kB Flash microcontroller with 1 kB RAM |
相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| P89LPC938FA,129 | 功能描述:8位微控制器 -MCU 80C51 8K FL 768B RAM 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 最大時鐘頻率:50 MHz 程序存儲器大小: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 安裝風格:SMD/SMT |
| P89LPC938FA129 | 制造商:NXP Semiconductors 功能描述:P89LPC938FA/PLCC28/TUBESM// |
| P89LPC938FDH | 制造商:NXP Semiconductors 功能描述:MCU 8BIT 80C51 8K FLASH TSSOP28 制造商:NXP Semiconductors 功能描述:MCU 8BIT 80C51 8K FLASH, TSSOP28 制造商:NXP Semiconductors 功能描述:MCU 8BIT 80C51 8K FLASH, TSSOP28, Controller Family/Series:(8051) 8052, Core Siz |
| P89LPC938FDH,529 | 功能描述:8位微控制器 -MCU 80C51 8K FL 768B RAM 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 最大時鐘頻率:50 MHz 程序存儲器大小: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 安裝風格:SMD/SMT |
| P89LPC938FDH529 | 制造商:NXP Semiconductors 功能描述:IC 8BIT MCU 80C51 18MHZ TSSOP-28 |
發(fā)布緊急采購，3分鐘左右您將得到回復。