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61 Threads found on External Rtc
Hi, It's not clear to me: is the rtc hardware or software? An rtc needs a clock. What clock source do you use? If it is an external hardware rtc with it's own xtal, then we need to see the PCB layout. Klaus
Even if you are able to determine the need to calibrate the Clock by adding/subtracting a certain amount of seconds per day, it is not accurate. There could remain fractions of a second which were not accounted on that automatic correction. If you want to have an accurate value, you should consider using external signal sources to periodically sync
Hello, I am using a PIC32 uC and on board space is critical. I have created a timer Interupt routine which constantly increments an extern variable. The count this variable holds is the number of 4 ms time slices. Therefore I am able to count the time slices and decern seconds, minutes, hours etc... My question is, I now need to make a cal
I decided to use an external rtc IC because of the power loss case. In that case, you may want to consider an rtc like the Maxim DS3234, there are breakout board readily available for the developer and open source libraries for AVR and Arduino.
Hi, I am using ATXMEGA16E5 in an application. And i use the rtc clock ( period 1 sec , external 32.768 clock) to wakeup from power save mode. After wake up i measure some ADC channels and after goes to power save mode. The program works well when no debugging. When i use the AtmelICE and i push HALT it does not stops, and IAR gives a error "
Looking at your schematic I presume that the power supply to the rtc is 5v and the backup is 3v (not 12 as shown)? You don't need external load capacitors but you have to make sure that the load capacitance of your crystal is 12.5pF - what is the load of your crystal. Where did you get your crystal from, those on E-bay are low quality and have qui
I was going through datasheet of pic micro-controller (PIC32MX795F512L) ans was wondering what the requirement of ppm for main clock (main clock i meant because there is also rtc crystal) was?? :bang: I have gone through few pic micro datasheets and found that none of them mention the ppm requirement for external crystal. Does anyone based on
Hai every one, I am using the internal rtc for my project to read the date and time, but some one said that external rtc has more advantages compared with the internal rtc why? what is the reason for that? please explain me what are the main difference between internal rtc and external (...)
The ceramic "supercap" is quite nice. But even with very low current consumption of the Abracon rtc, it will provide backup only for a few days. That may be too short for many applications. The Abracon rtc doesn't recharge the capacitor, you need an external low leakage diode.
Hi, Apart from the fact that the 16f84 is virtually obselete, a lot of basic differences, just compare the two datasheets. In respect of a "timer" is hard to say as that can cover such a wide range of possibilities; are you talking of a nano seconds timer or days and months ? Are you wanting to use an external rtc clock like the DS1307 wh
Can you wrap this as code rather then text? Some more information: 1.) Circuit setup 2.) Interrupt setup (I see that is called but I don't see where you do this at) 3.) Address definitions Hi..greg Here is my ISR and Address definitions... void rtcINTInit(void) { PORTSetPinsD
You have already mentioned the relevant options. In addition, a watchdog or low power timer may be provided by the processor. If you want an exact timing, external rtc interrupt is probably the only reasonable method. I presume, you don't need to sleep the processor for exactly 5 minutes. If power saving is the objective, a sufficient low interrupt
Integrated: Means in built crystal. Which is best option because external crystal increase cost, space. Use it if possible plz share it's part no.For more details u can refer following link also :
PIC12F1822 have 256bytes EEPROM size, to store more data you need external EEPROM IC. You can use I2C/SPI protocol for this. One question you need real time to say when motor is off like 13:40:07-14:02:34 ? In that case you need to use rtc IC. How long you need to log this few hours, one day, week, month, ... ? You need to determine needed si
Hi guys, My problems is the lack of information in "GE864-GPS Hardware User Guide". In the section about GPS_WAKEUP and GPS_ON_OFF signals they say : The GPS starts after asserting a rising edge pulse on GPS_ON_OFF input and when high level persists for at least three cycles of rtc clock. Before asserting another pulse to GPS_ON_OFF
For voltage sensing, you can use a voltage divider and sense the voltage using the PIC ADC module. For date and time, you can use a rtc chip and interface it to PIC16F877A. You can use DS1307 and interface it to PIC16F877A using I2C protocol. You may save the data on the PIC EEPROM or you may use an external memory for larger storage space, eg an
I somewhat agree, however the cost of implementing an external rtc controller would be more than implementing a battery backup on the PIC's power supply. It would be nice to have the option of just connecting a battery though, with built-in switch over on main power loss. (Are you listening, Microchip?)
The ds1307 uses an external crystal. I think that the accuracy depends more on the crystal and related components that you use rather than the chip. Using the right crystal with good ppm deviation will improve the accuracy. See the DS were it says: Note: For more information on crystal selection and crystal layout considerations, r
If you using the Hi-Tech PICC18 compiler why not use the provided I2C libraries? Example accessing external I2C Serial EEPROM: // will automatically include peripheral library header files #include unsigned char arraywr = {1,2,3,4,5,6,7,8,0}; unsigned char arrayrd; //***************************************************
/***************************************************** Project : rtc Version : V1 Date : 5/17/2012 Author : Swaminathan Balagangatharan Company : PARC Comments: Chip type : ATmega16 Program type : Application Clock frequency : 11.059200 MHz Memory model : Small external RAM size : 0 Data Sta
Dear Friends, I am working on LPC2368 I am trying operate rtc from external OSC Can anybody please help me out with initialization steps
I got a problem when using a PCF8563 rtc with a Capacitor based power supply for 5V. The circuit created for the purpose is shown in the attached file. The issue is with the accuracy. When the same circuit is connected to a pure 5V dc supply from an external power source, the rtc gives me exactly 1Hz pulse at the ClKOUT pin of the IC, and (...)
Hi, On the Pics /4550 you connect a 32k crystal and caps as shown below, this is then used as the clock source to Timer1 as a rtc. On a ATMEGA32 I believe its very similar, according to the datasheet pins PC6 and PC7 are the input to its Timer1 , but it only needs the crystal, caps not required. Timer/Counter Oscillator For AVR micr
Hi. Im new learner for MikroC. I doing automated meter reading using rf. Transmitter is connected to the electric meter and it counts the pulses from it and displays it over the LCD display. It also transmits the data over wireless using RF. and i added few thing like rtc for clock and external EEprom for storing meter reading. rtc and (...)
LPC2148 has inbuilt low power rtc. You don't need to interface any external rtc. Go through the user manual of LPC2148.
Yes timer2 can work asynchronous using an external crystal of 32768 Hz. Check the datasheet page 117-120 Alex
If you work with a crystal multiple of 2 ( i.e. 32,768 KHz used at rtc ), yes you can obtain the exact value generating some interruption. However, due that frequency is very slow to most applications, the best choice could be using this at external oscilator generating interrupt on pin. +++
The SCL and SDA lines need to be pulled up; have you done that? You could use either external 4.7k(s) or enable the internal weak pullups available on the 18F4455 port B. Regards, Anand Dhuru
all the software libraries are tested before giving to external world and cannot be simply challenged..... i never got any problem if i use inbuilt libraries......
Precision rtc using ATMega8 and DS3231. Indication: 4-digit 7-segment (up to 42V 500mA on each segment), remote control (Sony RM887), temperature sensor (external DS18B20 or internal from DS3231), brightness correction with external photoresistor. Additional work mode - show static 4-digit number (fuel price etc). Schematics/PCB in (...)
Hi 2 all, why we are using external clock 32.786KHz for function of rtc?why won't we get 32.786KHZ frequency using control registers which is inbuilt? Thanks in advance regards JYOTHI
hi the problem here is that when the system is expecting something from the external device,(like the rtc) it halts. the i2c routine is expecting the ack from the rtc which will not get from the software simulator. just make the hardware (i think this is a small project and the hardware can be made easily) the system must work. ml
Hi WStevens, first of all I'm learning MCU programming so I could be wrong. Anyway, this is the ISR code I used with the same microprocessor (f877A) to simulate a clock, last year, with an external clock (Xtal=20MHz), prescaler=32, TMR0 (preload time) =100 (it should be 102 but, trying and retrying, I've seen that 100 was the best). It's not very p
external devices, like EEPROM, rtc, A/D generally operates at maximum frequency from 100KHz up to 400KHz. +++
Different PIC24 processors have different rtcC clock options. Some allow to select the LPRC oscillator (which isn't actually suited for an accurate real time clock, but e.g. for other timing purposes). The PIC24FxxGA002 rtc can only run from external SOSC oscillator (using a 32 kHz watch crystal).
The ready made clock chips available, usually use mains frequency as refernce and thus the accuracy highly depends on the same. But you can get dead accuracy with rtc interfaced with a microcontroller. But In the DS1307 as it uses external cylinderical crystal, the accuracy may not be guaranteed. But using a DS12887 module accurate time can be obta
C will be more suitable. For real time, it is better to use an external rtc chip with the PIC or use a PIC with internal rtc. The oscillator can be internal or external, I guess no problem with taht. -- Amr
Hi, first post so be gentle:) Also had a search but couldn't find anything. Basically what I want to do is connect a rubidium oscillator to a PIC (perhaps via a rtc) and output the accurate time to a set of Nixie tubes. The atomic output is 10Mhz and doesn't have a 1Hz option. Could I just sync the PIC clock to 10Mhz using the external clo
Hello, I'm interested in build one chronometer to count from 0,001s to 9,999s The input of the system is one interrupt in one PIC microcontroller. My questions: - Why normally in the rtc the people use one crystal of 32,768KHz ? - If I use one external crystal of 32,768KHz in one timer, I have one resolution of 0.000305 seconds that is v
I am using 20 PPM external crystal oscillator in rtc because of 20 PPM it shell be give 1.33 sec delay per day how can I calculate the error in this external crystal.
hello all... i think this is the silly question...but really i am confusing here plz anybody help me i am using here msp430 controller and this is inbuilt rtc. i want battery backup for this controller so shell i use external SRAM for this purpose? and my msp430 have 116KB+256B Flash or ROM† Memory, 8KB RAM so plz tell me wat i do?
I am learning rtc and I want to know the mothod to detect external power supply after the battery is installed. Though some analog ways, I wanna digital methods. Thanks!
Hi, I have been working on a problem for days and I run out of ideas. I got an Atemga644PV with an external rtc clock (32kHz) on TOSC1 and 2 for async timer2. I use pcint21 to read (count) some impulses but the higher the signal the more the rtc is affected to the point of stoping working. I have tried: - JTAG disabled - Capacitors (...)
Hello, I am looking for a ready made "Timer module" which will show time in Hour:Min:sec format once turned on....... It can be paused with external pulse. I have searched a lot on google for it, but I am getting ICs and rtc for it but not readymade module I want the ready made plug n play module for my project........... Kindly give me
Sorry for the sort of lame question, but.... I am using a DS1339 rtc and it calls for a pullup from the SQW/INT pin to Vcc. It is there in the schematics but no value is given. The only thing they say is: "The SQW/INT pin is an open-drain output and requires an external pullup resistor. " My Vcc is 3.3v, so what value should I have as the p
Hi As given in datasheet of mega128, many peripheral devices such as rtcs, LCDs can be interfaced with the external memory port given to mega128. Can anybody post a link of tutorial/application note regarding this? Here are my doubts, 1. I think this is an intel type uC (it has ALE, RDbar, WRbar etc.). So when running external device (...)
hi all.. i'm working on project creating datalogger using AVR ATMega8535, i using rtc DS1307 conect to AVR : SDA --> PB0, SCL --> PB1 for time stamp and store log data using EEPROM 24C256 , code for rtc i create using CVAVR that have built in code to run rtc DS1307 and it works, but for storing logged data to external (...)
Hello I need C code of rtc(external crystal) for LPC2138
Hello I need C code of rtc(external crystal) for LPC2138
Hello I need C code of rtc for LPC2138