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    參數(shù)資料
    型號(hào)： P89C660HBBD
    廠商： NXP SEMICONDUCTORS
    元件分類： 微控制器/微處理器
    英文描述： 80C51 8-bit Flash microcontroller family
    中文描述： 8-BIT, FLASH, 33 MHz, MICROCONTROLLER, PQFP44
    封裝： 10 X 10 MM, 1.40 MM HEIGHT, PLASTIC, MS-026, SOT-389-1, LQFP-44
    文件頁(yè)數(shù)： 35/89頁(yè)
    文件大小： 491K
    代理商： P89C660HBBD
    Philips Semiconductors
    Product data
    P89C660/P89C662/P89C664/
    P89C668
    80C51 8-bit Flash microcontroller family
    16KB/32KB/64KB ISP/IAP Flash with 512B/1KB/2KB/8KB RAM
    2002 Oct 28
    35
    TIMER 2 OPERATION
    Timer 2
    Timer 2 is a 16-bit Timer/Counter which can operate as either an
    event timer or an event counter, as selected by C/T2 in the special
    function register T2CON (see Figure 20). Timer 2 has three operating
    modes:
    – Capture Mode
    – Auto-Reload Mode (up or down counting)
    – Baud Rate Generator Mode (see Table 10)
    Capture Mode
    In the capture mode there are two options which are selected by bit
    EXEN2 in T2CON. If EXEN2 = 0, then Timer 2 is a 16-bit timer or
    counter (as selected by C/T2 in T2CON) which, upon overflowing
    sets bit TF2, the Timer 2 overflow bit. This bit can be used to
    generate an interrupt (by enabling the Timer 2 interrupt bit in the
    IE register). If EXEN2 = 1, Timer 2 operates as described above,
    with the added feature that a 1-to-0 transition at external input pin
    T2EX causes the current value in the Timer 2 registers, TL2 and
    TH2, to be captured into registers RCAP2L and RCAP2H. In
    addition, the transition at T2EX causes bit EXF2 in T2CON to be
    set. If Timer 2 interrupt has been enabled, EXF2 will generate an
    interrupt (which vectors to the same location as Timer 2 overflow
    interrupt). The Timer 2 interrupt service routine can interrogate TF2
    and EXF2 to determine which event caused the interrupt. The
    capture mode is illustrated in Figure 21 (There is no reload value for
    TL2 and TH2 in this mode). Even when a capture event occurs from
    T2EX, the counter keeps on counting T2EX pin transitions or osc/6
    pulses (osc/12 in 12 clock mode).
    Auto-Reload Mode (Up or Down Counter)
    In the 16-bit auto-reload mode, Timer 2 can be configured as either
    a timer or counter (C/T2 in T2CON), then programmed to count up
    or down. The counting direction is determined by bit DCEN (Down
    Counter Enable) which is located in the T2MOD register (see
    Figure 22). When reset is applied (DCEN = 0), Timer 2 defaults to
    counting up. If DCEN bit is set, Timer 2 can count up or down
    depending on the value of the T2EX pin.
    Figure 23 shows Timer 2 which will count up automatically since
    DCEN = 0. In this mode there are two options selected by bit
    EXEN2 in T2CON register. If EXEN2 = 0, then Timer 2 counts up to
    0FFFFH and sets the TF2 (Overflow Flag) bit upon overflow. This
    causes the Timer 2 registers to be reloaded with the 16-bit value in
    RCAP2L and RCAP2H. The values in RCAP2L and RCAP2H are
    preset by software.
    If EXEN2 = 1, then a 16-bit reload can be triggered either by an
    overflow or by a 1-to-0 transition at input pin T2EX. This transition
    also sets the EXF2 bit. The Timer 2 interrupt, if enabled, can be
    generated when either TF2 or EXF2 are 1.
    In Figure 24 DCEN = 1 which enables Timer 2 to count up or down.
    This mode allows pin T2EX to control the direction of count. When a
    logic 1 is applied at pin T2EX Timer 2 will count up. Timer 2 will
    overflow at 0FFFFH and set the TF2 flag, which can then generate
    an interrupt, if the interrupt is enabled. This timer overflow also
    causes the 16-bit value in RCAP2L and RCAP2H to be reloaded
    into the timer registers TL2 and TH2.
    When a logic 0 is applied at pin T2EX this causes Timer 2 to count
    down. The timer will underflow when TL2 and TH2 become equal to
    the value stored in RCAP2L and RCAP2H. Timer 2 underflow sets
    the TF2 flag and causes 0FFFFH to be reloaded into the timer
    registers TL2 and TH2.
    The external flag EXF2 toggles when Timer 2 underflows or overflows.
    This EXF2 bit can be used as a 17th bit of resolution if needed. The
    EXF2 flag does not generate an interrupt in this mode of operation.
    (MSB)
    (LSB)
    Symbol
    Position
    Name and Significance
    TF2
    T2CON.7
    Timer 2 overflow flag set by a Timer 2 overflow and must be cleared by software. TF2 will not be set
    when either RCLK or TCLK = 1.
    Timer 2 external flag set when either a capture or reload is caused by a negative transition on T2EX and
    EXEN2 = 1. When Timer 2 interrupt is enabled, EXF2 = 1 will cause the CPU to vector to the Timer 2
    interrupt routine. EXF2 must be cleared by software. EXF2 does not cause an interrupt in up/down
    counter mode (DCEN = 1).
    Receive clock flag. When set, causes the serial port to use Timer 2 overflow pulses for its receive clock
    in modes 1 and 3. RCLK = 0 causes Timer 1 overflow to be used for the receive clock.
    Transmit clock flag. When set, causes the serial port to use Timer 2 overflow pulses for its transmit clock
    in modes 1 and 3. TCLK = 0 causes Timer 1 overflows to be used for the transmit clock.
    Timer 2 external enable flag. When set, allows a capture or reload to occur as a result of a negative
    transition on T2EX if Timer 2 is not being used to clock the serial port. EXEN2 = 0 causes Timer 2 to
    ignore events at T2EX.
    Start/stop control for Timer 2. A logic 1 starts the timer.
    Timer or counter select. (Timer 2)
    0 = Internal timer (OSC/6 in 6-clock mode or OSC/12 in 12-clock mode)
    1 = External event counter (falling edge triggered).
    Capture/Reload flag. When set, captures will occur on negative transitions at T2EX if EXEN2 = 1. When
    cleared, auto-reloads will occur either with Timer 2 overflows or negative transitions at T2EX when
    EXEN2 = 1. When either RCLK = 1 or TCLK = 1, this bit is ignored and the timer is forced to auto-reload
    on Timer 2 overflow.
    EXF2
    T2CON.6
    RCLK
    T2CON.5
    TCLK
    T2CON.4
    EXEN2
    T2CON.3
    TR2
    C/T2
    T2CON.2
    T2CON.1
    CP/RL2
    T2CON.0
    TF2
    EXF2
    RCLK
    TCLK
    EXEN2
    TR2
    C/T2
    CP/RL2
    SU01251
    Figure 20. Timer/Counter 2 (T2CON) Control Register
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    相關(guān)代理商/技術(shù)參數(shù)
    參數(shù)描述
    P89C660HBBD/00,557 功能描述:8位微控制器 -MCU 16K/512 FL 6 CLK ISP/IAP COM 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(shí)鐘頻率:50 MHz 程序存儲(chǔ)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
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    P89C662 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:On-chip Flash 8-bit microcontroller Errata Sheet
    P89C662HBA 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:80C51 8-bit Flash microcontroller family
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