problem with RTC

[mailtoarup]

Posted on September 17, 2003 at 04:19

problem with RTC

[mailtoarup]

Posted on September 11, 2003 at 03:35

Hello sir,

I was working with Indart demo board using Indart-St72F264 ICD…….. I have populated two Ics( M24C08 & DS1307)….on the bread board area provided in the demo board….. And when I was communicating EEPROM(24c0 with St72F264 thro i2c communication ,then there was no problem .But when I am using RTC(DS1307-dallas semiconductor) and going thro Indart-St7 dubugger then program was not running…and was showing COMMUNICATION error………I did not use battery with the rtc. .Infact crystal was not running to its actual frequency(768KHz) . My circuit arrangement is like that….****************************************** The micro is 32 pin ic. I have connected pin no 5 & 6 of DS1307 to pin PA6 & PA4 of the micro respectively. Now connection for DS1307 :: Between pin no 1 & 2 (DS1307) connected the crystal (768 KHz)….. A capacitor (22 pF) is connected between pin 1 & GND .Another capacitor (22 pF) is connected Between pin no 2 & GND. Between pin no 4 & 8 connected a capacitor(100 nF).and pin no 4 is connected to GND. Pin no 8 is connected to Vcc(supply: 5 V D.C).pin no 8 is also connected to anode of diode(IN4007).cathode is connected to a resistance of (1K).other end of the resistance is connected to Pin no 3. Pin no 7 is connected to reset pin Micro thro’ a zero ohm resistor. Actually pin no 3 is connected to GND thro’ battery(I have ommited this connection as I don’t need battery back up at his moment , this could be a problem??) Please tell me is this arrangement is ok…….what is the cause of this problem??? pls help me in rectyfying this problem….. Thanks & Regards Arup

[sjo]

Posted on September 11, 2003 at 06:51

I would guess the problem is pin 7 of the DS1307, as you say it is connected to the micro reset pin - why ? - disconnect this pin as it is probably reseting the micro.

I would also leave pin 3 disconnected is you have no battery, the device will only use the battery when the main power is lost anyway. I have not used this device, but have used the very similar MK41T56 Hope this is of help Regards sjo

[itsmejatinus]

Posted on September 12, 2003 at 14:40

Can you provide the data sheet for the RTC?

[mailtoarup]

Posted on September 17, 2003 at 04:19

hi ranjeet,

i m attaching DS1. tell me wht steps to follow to interface rtc with micro in assembly language.. i mean wht registers should be initialized..and how... pls help thanks arup ________________ Attachments : DS1307.pdf : https://st--c.eu10.content.force.com/sfc/dist/version/download/?oid=00Db0000000YtG6&ids=0680X000006I0CJ&d=%2Fa%2F0X0000000bV8%2FDTWe1HKrMZ.mkIRaFXdovvhNJFzXO2Q4vyAU4ftJT2U&asPdf=false