Connecting DS1302 with DS32kHz

jcolonias

Hi,

·I would like to connect the DS1302 with the DS32kHz in the fashion shown in the attached
schematic. However, since I am a notice, I would appreciate those of you knowledgeable to
look it over and tell me if it is OK.

I intend to use Jon Williams's N&V #33 and 34 for programming.

Thanks very much!

John

Forrest

I don't know what a DS32KHz is - but this looks like a simpler circuit for the DS1302 http://forums.parallax.com/showthread.php?p=531080

allanlane5

Good -- I thought pin 1 was for 5-volts, while pin 8 was for battery-backup 3-volts.

The DS1302 keeps time through power-outages by using pin 8 power, and running a low-power crystal-based oscillator. I don't know how this scenario would work with an external chip generating the 32 Khz signal. On the one hand, it should be MUCH more accurate -- and I believe MAXIM designed the external chip to run WITH the 1302 in mind.

On the other hand, now the DS32Khz MUST have battery backup also, no?

P.S. Okay, I looked at the Maxim-IC site.· Yes, the DS32Khz must have battery backup too -- though it looks like it can connect to the 1302 battery.· The combination of the two devices has about 1.5 uA of current from a 3-volt coin cell to work, using a 1302 (first generation 'N' type).


Post Edited (allanlane5) : 4/18/2005 9:11:43 PM GMT

Chris Savage

John,

·· Don't know much about the DS32khz, but i can tell you the circuit won't work if you don't connect pin 4 to ground.

Allan,

·· The DS1302 will run from whatever voltage is greater, that on pin 1, or that on pin 8, within it's operating range.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Chris Savage
Parallax Tech Support
csavage@parallax.com