參數(shù)資料
型號(hào): DS14287
英文描述: Real Time Clock with NV RAM Control
中文描述: 實(shí)時(shí)時(shí)鐘,帶有非易失RAM控制器
文件頁(yè)數(shù): 14/25頁(yè)
文件大?。?/td> 303K
代理商: DS14287
DS14285/DS14287
14 of 25
that bits which are set remain stable throughout the read cycle. All bits which are set (high) 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 second flag bit usage method is with fully enabled interrupts. When an interrupt flag bit is set and the
corresponding interrupt enable bit is also set, the
IRQ
pin is asserted low.
IRQ
is asserted as long as at
least one of the three interrupt sources has its flag and enable bits both set. The IRQF bit in Register C is
a one whenever the
IRQ
pin is being driven low. Determination that the RTC initiated an interrupt is
accomplished by reading Register C. A logic one in bit 7 (IRQF bit) indicates that one or more interrupts
have been initiated by the DS14285/DS14287. The act of reading Register C clears all active flag bits and
the IRQF bit.
PERIODIC INTERRUPT SELECTION
The periodic interrupt will cause the
IRQ
pin to go to an active state from once every 500 ms to once
every 122
μ
s. This function is separate from the alarm interrupt which can be output from once per
second to once per day. The periodic interrupt rate is selected using the same Register A bits which select
the square wave frequency (see Table 2). Changing the Register A bits affects both the square wave
frequency and the periodic interrupt output. However, each function has a separate enable bit in Register
B. The SQWE bit controls the square wave output. Similarly, the periodic interrupt is enabled by the PIE
bit in Register B. The periodic interrupt can be used with software counters to measure inputs, create
output intervals, or await the next needed software function.
OSCILLATOR CONTROL BITS
When the DS14287 is shipped from the factory, the internal oscillator is turned off. This feature prevents
the lithium energy cell from being used until it is installed in a system. A pattern of 010 in bits 4 through
6 of Register A will turn the oscillator on and enable the countdown chain. A pattern of 11X will turn the
oscillator on, but holds the countdown chain of the oscillator in reset. All other combinations of bits 4
through 6 keep the oscillator off.
SQUARE WAVE OUTPUT SELECTION
Thirteen of the 15 divider taps are made available to a 1-of-15 selector, as shown in the block diagram of
Figure 1. The first purpose of selecting a divider tap is to generate a square wave output signal on the
SQW pin. The RS0-RS3 bits in Register A establish the square wave output frequency. These
frequencies are listed in Table 2. The SQW frequency selection shares its 1-of-15 selector with the
periodic interrupt generator. Once the frequency is selected, the output of the SQW pin can be turned on
and off under program control with the square wave enable bit (SQWE).
相關(guān)PDF資料
PDF描述
DS14285-DS14287 Real Time Clock with NV RAM Control
DS14285 Real Time Clock with NV RAM Control
DS14285N Real Time Clock with NV RAM Control
DS14285Q Real Time Clock with NV RAM Control
DS14285QN Real Time Clock with NV RAM Control
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
DS14287+ 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
DS1-48-0001 功能描述:固定電感器 DS Storage choke 3.15A RoHS:否 制造商:AVX 電感:10 uH 容差:20 % 最大直流電流:1 A 最大直流電阻:0.075 Ohms 工作溫度范圍:- 40 C to + 85 C 自諧振頻率:38 MHz Q 最小值:40 尺寸:4.45 mm W x 6.6 mm L x 2.92 mm H 屏蔽:Shielded 端接類型:SMD/SMT 封裝 / 箱體:6.6 mm x 4.45 mm
DS1-48-0002 功能描述:固定電感器 DS Storage choke 4A RoHS:否 制造商:AVX 電感:10 uH 容差:20 % 最大直流電流:1 A 最大直流電阻:0.075 Ohms 工作溫度范圍:- 40 C to + 85 C 自諧振頻率:38 MHz Q 最小值:40 尺寸:4.45 mm W x 6.6 mm L x 2.92 mm H 屏蔽:Shielded 端接類型:SMD/SMT 封裝 / 箱體:6.6 mm x 4.45 mm
DS1-48-0003 制造商:Schurter Electronic Components 功能描述:
DS1-48-0004 制造商:Schurter Electronic Components 功能描述: