- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄255834 > BQ4285LS-N (TEXAS INSTRUMENTS INC) 1 TIMER(S), REAL TIME CLOCK, PDSO24 PDF資料下載
參數(shù)資料
| 型號： | BQ4285LS-N |
| 廠商： | TEXAS INSTRUMENTS INC |
| 元件分類： | XO, clock |
| 英文描述： | 1 TIMER(S), REAL TIME CLOCK, PDSO24 |
| 封裝： | SOIC-24 |
| 文件頁數(shù)： | 28/30頁 |
| 文件大小： | 1497K |
| 代理商： | BQ4285LS-N |
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頁當(dāng)前第28頁第29頁第30頁
Alarm Interrupt
The alarm interrupt request is valid in battery-backup
mode, providing a “wake-up” capability. During each up-
date cycle, the RTC compares the hours, minutes, and
seconds bytes with the three corresponding alarm bytes.
If a match of all bytes is found, the alarm interrupt
event flag bit, AF in register C, is set to 1. If the alarm
event is enabled, an interrupt request is generated.
An alarm byte may be removed from the comparison by
setting it to a “don’t care” state. An alarm byte is set to a
“don’t care” state by writinga1toeachofits two most-
significant bits. A “don’t care” state may be used to select
the frequency of alarm interrupt events as follows:
n
If none of the three alarm bytes is “don’t care,” the
frequency is once per day, when hours, minutes, and
seconds match.
n
If only the hour alarm byte is “don’t care,” the
frequency is once per hour, when minutes and
seconds match.
n
If only the hour and minute alarm bytes are “don’t care,”
the frequency is once per minute, when seconds match.
n
If the hour, minute, and second alarm bytes are
“don’t care,” the frequency is once per second.
Update Cycle Interrupt
The update cycle ended flag bit (UF) in register C is set to
a 1 at the end of an update cycle. If the update interrupt
enable bit (UIE) of register B is 1, and the update transfer
inhibit bit (UTI) in register B is 0, then an interrupt re-
quest is generated at the end of each update cycle.
Accessing RTC bytes
Time and calendar bytes read during an update cycle
may be in error. Three methods to access the time and
calendar bytes without ambiguity are:
n
Enable the update interrupt event to generate
interrupt requests at the end of the update cycle.
The interrupt handler has a maximum of 999ms to
access the clock bytes before the next update cycle
begins (see Figure 3).
n
Poll the update-in-progress bit (UIP) in register A. If
UIP = 0, the polling routine has a minimum of tBUC
time to access the clock bytes (see Figure 3).
n
Use
the
periodic
interrupt
event
to
generate
interrupt requests every tPI time, such that UIP = 1
always occurs between the periodic interrupts. The
interrupt handler will have a minimum of
tPI/2 +
tBUC time to access the clock bytes (see Figure 3).
Oscillator Control
When power is first applied to the bq4285E/L and VCC is
above VPFD, the internal oscillator and frequency divider
are turned on by writing a 010 pattern to bits 4 through 6
of register A. A pattern of 011 behaves as 010 but addi-
tionally transforms register C into a read/write register.
This allows the 32.768kHz output on the square wave pin
to be turned on. A pattern of 11X turns the oscillator on,
but keeps the frequency divider disabled. Any other pat-
tern to these bits keeps the oscillator off.
7
bq4285E/L
Figure 3. Update-Ended/Periodic Interrupt Relationship
Jan. 1999 B
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| BQ4285LSNTR | 1 TIMER(S), REAL TIME CLOCK, PDSO24 |
| BX80616I5650SLBLK | 64-BIT, 133 MHz, MICROPROCESSOR, PBGA1156 |
| BP83C51FA | 8-BIT, MROM, 12 MHz, MICROCONTROLLER, PDIP40 |
| BU2465F | 4-BIT, MROM, 1 MHz, MICROCONTROLLER, PDSO18 |
| BU2419F-T1 | 4-BIT, MROM, 1 MHz, MICROCONTROLLER, PDSO22 |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| BQ4285LSTR | 制造商:TI 制造商全稱:Texas Instruments 功能描述:Enhanced RTC With NVRAM Control |
| BQ4285P- | 制造商:TI 制造商全稱:Texas Instruments 功能描述:Real-Time Clock RTC With NVRAM Control |
| BQ4285P-SB2 | 功能描述:實時時鐘 RTC IC: 114x8 NVSRAM & NVSRAM Control 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 時間格式:HH:MM:SS RTC 存儲容量: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 |
| BQ4285Q- | 制造商:TI 制造商全稱:Texas Instruments 功能描述:Real-Time Clock RTC With NVRAM Control |
| BQ4285S- | 制造商:TI 制造商全稱:Texas Instruments 功能描述:Real-Time Clock RTC With NVRAM Control |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。