參數(shù)資料
型號(hào)： DS1689
廠商： DALLAS SEMICONDUCTOR
元件分類： Timer or RTC
英文描述： 1 TIMER(S), REAL TIME CLOCK, PDIP28
封裝： 0.600 INCH, DIP-28
文件頁(yè)數(shù)： 32/32頁(yè)
文件大?。?/td> 376K
代理商： DS1689
DS1689/DS1693
9 of 32
will immediately be set at an active level, even though the event initiating the interrupt condition may
have occurred much earlier. As a result, there are cases where the software should clear these earlier
generated interrupts before first enabling new interrupts.
When an interrupt event occurs, the relating flag bit is set to a logic 1 in Register C or in Extended
Register A. These flag bits are set regardless of the setting of the corresponding enable bit located either
in Register B or in Extended Register B. The flag bits can be used in a polling mode without enabling the
corresponding enable bits.
However, care should be taken when using the flag bits of Register C as they are automatically cleared to
0 immediately after they are read. Double latching is implemented on these bits so that bits which are set
remain stable throughout the read cycle. All bits which were set are cleared when read and new interrupts
which are pending during the read cycle are held until after the cycle is completed. One, 2, or 3 bits can
be set when reading Register C. Each utilized flag bit should be examined when read to ensure that no
interrupts are lost.
The flag bits in Extended Register A are not automatically cleared following a read. Instead, each flag bit
can be cleared to 0 only by writing 0 to that bit.
When using the flag bits with fully enabled interrupts, the IRQ line will be driven low when an interrupt
flag bit is set and its corresponding enable bit is also set. IRQ will be held low as long as at least one of
the six possible interrupt sources has it s flag and enable bits both set. The IRQF bit in Register C is a 1
whenever the IRQ pin is being driven low as a result of one of the six possible active sources. Therefore,
determination that the DS1689/DS1693 initiated an interrupt is accomplished by reading Register C and
finding IRQF=1. IRQF will remain set until all enabled interrupt flag bits are cleared to 0.
SQUARE WAVE OUTPUT SELECTION
The SQW pin can be programmed to output a variety of frequencies divided down from the 32.768 kHz
crystal tied to X1 and X2. The square wave output is enabled and disabled via the SQWE bit in Register
B. If the square wave is enabled (SQWE=1), then the output frequency will be determined by the settings
of the E32K bit in Extended Register B and by the RS3-0 bits in Register A. If the E32K = 1, then a
32.768 kHz square wave will be output on the SQW pin regardless of the settings of RS3-0.
If E32K = 0, then the square wave output frequency is determined by the RS3-0 bits. These bits control a
1-of-15 decoder which selects one of 13 taps that divide the 32.768 kHz frequency. The RS3-0 bits
establish the SQW output frequency as shown in Table 2. In addition, RS3-0 bits control the periodic
interrupt selection as described below.
If SQWE1, E32K=1, and the Auxiliary Battery Enable bit (ABE, bank 1; register 04BH) is enabled, and
voltage is applied to VBAUX then the 32 kHz square wave output signal will be output on the SQW pin in
the absence of VCC. This facility is provided to clock external power management circuitry. If any of the
above requirements are not met, no square wave output signal will be generated on the SQW pin in the
absence of VCC.
A pattern of 01X in the DV2, DV1, and DV0, bits respectively, will turn the oscillator on and enable the
countdown chain. Note that this is different than the DS1287, which required a pattern of 010 in these
bits. DV0 is now a “don’t care” because it is used for selection between register banks 0 and 1.
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
DS1689_05 制造商:DALLAS 制造商全稱:Dallas Semiconductor 功能描述:3V/5V Serialized Real-Time Clocks with NV RAM Control
DS1689S 功能描述:實(shí)時(shí)時(shí)鐘 RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 總線接口:I2C 日期格式:DW:DM:M:Y 時(shí)間格式:HH:MM:SS RTC 存儲(chǔ)容量:64 B 電源電壓-最大:5.5 V 電源電壓-最小:1.8 V 最大工作溫度:+ 85 C 最小工作溫度: 安裝風(fēng)格:Through Hole 封裝 / 箱體:PDIP-8 封裝:Tube
DS1689S/R 制造商:DALLAS 制造商全稱:Dallas Semiconductor 功能描述:3V/5V Serialized Real-Time Clocks with NV RAM Control
DS1689S/T 制造商:DALLAS 制造商全稱:Dallas Semiconductor 功能描述:3V/5V Serialized Real-Time Clocks with NV RAM Control
DS1689S/T&R 制造商:Rochester Electronics LLC 功能描述:
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