您的位置：维库电子市场网 > Datasheet > DS1554W-120

DS1554W-120 Datasheet

  • DS1554W-120

  • 256K NV Y2KC Timekeeping RAM

  • 285.66KB

  • 21页

  • DALLAS   DALLAS

阅览下载 纠错 0

扫码查看芯片数据手册

上传产品规格书

PDF预览

DS1554
The
IRQ
/FT pin can also be activated in the battery backed mode. The
IRQ
/FT will go low if an alarm
occurs and both ABE and AE are set. The ABE and AE bits are cleared during the power-up transition,
however an alarm generated during power-up will set AF. Therefore the AF bit can be read after system
power-up to determine if an alarm was generated during the power-up sequence. Figure 4 illustrates alarm
timing during the battery back-up mode and power-up states.
BACK-UP MODE ALARM WAVEFORMS Figure 4
USING THE WATCHDOG TIMER
The watchdog timer can be used to detect an out-of-control processor. The user programs the watchdog
timer by setting the desired amount of time-out into the 8-bit Watchdog Register (Address 7FF7h). The
five Watchdog Register bits BMB4-BMB0 store a binary multiplier and the two lower order bits RB1-
RB0 select the resolution, where 00=1/16 second, 01=1/4 second, 10=1 second, and 11=4 seconds. The
watchdog time-out value is then determined by the multiplication of the 5-bit multiplier value with the 2-
bit resolution value. (For example: writing 00001110 in the Watchdog Register = 3 X 1 second or 3
seconds.) If the processor does not reset the timer within the specified period, the Watchdog Flag (WF) is
set and a processor interrupt is generated and stays active until either the Watchdog Flag (WF) is read or
the Watchdog Register (7FF7) is read or written.
The most significant bit of the Watchdog Register is the Watchdog Steering Bit (WDS). When set to a 0,
the watchdog will activate the
IRQ
/FT output when the watchdog times out.
When WDS is set to a 1, the watchdog will output a negative pulse on the
RST
output for a duration of
40 ms to 200 ms. The Watchdog Register (7FF7) and the FT bit will reset to a 0 at the end of a watchdog
time-out when the WDS bit is set to a 1.
The watchdog timer resets when the processor performs a read or write of the Watchdog Register. The
time-out period then starts over. The watchdog timer is disabled by writing a value of 00h to the
Watchdog Register. The watchdog function is automatically disabled upon power-up and the Watchdog
Register is cleared. If the watchdog function is set to output to the
IRQ
/FT output and the frequency test
function is activated, the watchdog function prevails and the frequency test function is denied.
9 of 21

DS1554W-120 产品属性

  • Lead (SnPb) Finish for COTSObsolescence Mitigation Program

  • 11

  • 集成电路 (IC)

  • 时钟/计时 - 实时时钟

  • -

  • 时钟/日历

  • 警报器，闰年，NVSRAM，监视计时器，Y2K

  • 32KB

  • HH:MM:SS（24 小时）

  • YY-MM-DD-dd

  • 并联

  • 2.97 V ~ 3.63 V

  • -

  • 0°C ~ 70°C

  • 通孔

  • 32-DIP 模块（0.600"，15.24mm）

  • 32-EDIP

  • 管件

DS1554W-120相关型号PDF文件下载

您可能感兴趣的PDF文件资料

热门IC型号推荐

©2024 维库电子市场网（www.dzsc.com）　备案号：浙B2-20050339-1 经营许可证：浙B2-20210386版权声明
买家服务热线：0571-85317607 | 买家服务部QQ： QQ:1609526468
卖家服务热线：0571-85317607 | 卖家服务部QQ： QQ:331652727

扫码下载APP，
一键连接广大的电子世界。

在线人工客服

买家服务：
卖家服务：

0571-85317607

客服在线时间周一至周五
9:00-17:30

关注官方微信号，
第一时间获取资讯。

建议反馈
返回顶部

建议反馈

联系人：

联系方式：

按住滑块，拖拽到最右边
>>
感谢您向阿库提出的宝贵意见，您的参与是维库提升服务的动力！意见一经采纳，将有感恩红包奉上哦！

PDF纠错X

投诉电话：0571-85317607 投诉QQ：

如选匿名将无法为您反馈投诉结果，建议实名投诉！