AN632 MAXIM [Maxim Integrated Products], AN632 Datasheet
AN632
Related parts for AN632
AN632 Summary of contents
Page 1
... Therefore, an initial offset calculation of ±1 second is within the resolution of the setup when testing for long-term RTC accuracy. The only issue now is the accuracy of the standard that the RTC time is being compared against, the PC clock. www.maxim-ic.com/an632 Application Note 632: Aug 01, 2001 Page ...
Page 2
... When the PC is turned off, the software clock stops running and loses all of its time-of-day information. For this reason, a hardware clock is also necessary. The hardware clock is either a separate real-time clock or a RTC function integrated into the PC's chipset. The hardware clock www.maxim-ic.com/an632 Page ...
Page 3
... Daytime Protocol or NTP. Client software that uses the Simple Network Time Protocol (SNTP) makes the same timing request as an NTP client, but does less processing and provides less accuracy. Table 1 summarizes the protocols and their port assignments. www.maxim-ic.com/an632 Page ...
Page 4
... Boulder, Colorado, to the public through their time and frequency services. At its source, UTC(NIST) is kept in as close agreement as possible with other national and international standards (typically within a few nanoseconds). www.maxim-ic.com/an632 Format in UTC seconds since January 1, 1900. ...
Page 5
... PC clock error in comparison to the NIST standard, you will need to wait between calibrations until the message in the main screen changes from "No server selected" line typically like "Server 2 selected using tcp port 13." At that time, another calibration can be performed. Figure 2. NISTIME 32 main screen www.maxim-ic.com/an632 Page ...
Page 6
... RTC hardware evaluation board MAXSMBUS module (PC parallel port to 3-wire serial conversion) RTC evaluation software PC Clock Calibration Software: NISTIME 32 Frequency Counter: Tektronix CMC251 Typical frequency is 32.768kHz +5V swing, 40% duty cycle Channel-A period measurement Pre-scale = IN Gate = X1000 Typical display reads 30.51758µs www.maxim-ic.com/an632 Page ...
Page 7
... Start the MAX6901 evaluation software, and stop cyclic burst reads. 8. Start NISTIME 32 software, and update the PC clock until the error between the PC clock and NIST time is less than 0.4 seconds. This may take more than one iteration to accomplish. www.maxim-ic.com/an632 +5V. The initial frequency ...
Page 8
... MORE INFORMATION MAX6900: QuickView -- Full (PDF) Data Sheet (584k) MAX6901: QuickView -- Full (PDF) Data Sheet (232k) MAX6902: QuickView -- Full (PDF) Data Sheet (216k) www.maxim-ic.com/an632 Offset Comments - After PC clock calibration with NIST After PC clock calibration with NIST -- Free Sample -- Free Sample -- ...