參數(shù)資料
型號: P89LPC902FN
廠商: NXP SEMICONDUCTORS
元件分類: 微控制器/微處理器
英文描述: 8-bit microcontrollers with two-clock 80C51 core 1 kB 3 V Flash with 128-byte RAM
中文描述: 8-BIT, FLASH, 7.3728 MHz, MICROCONTROLLER, PDIP8
封裝: 0.300 INCH, PLASTIC, MO-001, SOT-97-1, DIP-8
文件頁數(shù): 39/55頁
文件大?。?/td> 1236K
代理商: P89LPC902FN
Philips Semiconductors
P89LPC901/902/903
8-bit microcontrollers with two-clock 80C51 core
Product data
Rev. 04 — 21 November 2003
39 of 55
9397 750 12293
Koninklijke Philips Electronics N.V. 2003. All rights reserved.
8.23 Keypad interrupt (KBI)
The Keypad Interrupt function is intended primarily to allow a single interrupt to be
generated when Port 0 is equal to or not equal to a certain pattern. This function can
be used for bus address recognition or keypad recognition. The user can configure
the port via SFRs for different tasks.
The Keypad Interrupt Mask Register (KBMASK) is used to define which input pins
connected to Port 0 can trigger the interrupt. The Keypad Pattern Register (KBPATN)
is used to define a pattern that is compared to the value of Port 0. The Keypad
Interrupt Flag (KBIF) in the Keypad Interrupt Control Register (KBCON) is set when
the condition is matched while the Keypad Interrupt function is active. An interrupt will
be generated if enabled. The PATN_SEL bit in the Keypad Interrupt Control Register
(KBCON) is used to define equal or not-equal for the comparison.
In order to use the Keypad Interrupt as an original KBI function like in 87LPC76x
series, the user needs to set KBPATN = 0FFH and PATN_SEL = 1 (not equal), then
any key connected to Port 0 which is enabled by the KBMASK register will cause the
hardware to set KBIF and generate an interrupt if it has been enabled. The interrupt
may be used to wake up the CPU from Idle or Power-down modes. This feature is
particularly useful in handheld, battery powered systems that need to carefully
manage power consumption yet also need to be convenient to use.
In order to set the flag and cause an interrupt, the pattern on Port 0 must be held
longer than 6 CCLKs.
8.24 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 P89LPC901/902/903 User’s Manualfor
more details.
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P89LPC902FN.129 制造商:NXP Semiconductors 功能描述:8BIT MCU 1K FLASH 89LC902 DIP8
P89LPC903 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:8-bit microcontrollers with two-clock 80C51 core 1 kB 3 V Flash with 128-byte RAM
P89LPC903FD 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:8-bit microcontrollers with two-clock 80C51 core 1 kB 3 V Flash with 128-byte RAM
P89LPC903FD,112 功能描述:8位微控制器 -MCU 80C51 1K FL 128B 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(fēng)格:SMD/SMT