sq7bti 20 Posted May 15, 2014 Share Posted May 15, 2014 (edited) Have you tried the NXP PCF2129A instead? The PCF2129A operates at 3.3V, embeds the quartz crystal and requires no passive components, except the 10kΩ pull-up resistors for the I²C bus. Actually, the LM4F120 / TM4C123 already includes a RTC, but the battery power line for LPM is connected to the main power line. I got it all up and running with 1307, just as I wrote: Vbus as supply (5V) and with 3.3V on pullup i2c resistors. PCF is not available in DIP, while DS1307 is. Thanks for the hint anyway. Addendum: Besides, the DS1307 features an NVRAM. Comes handy for the project I am working on right now: newtonian telescope controller: store mount specific configuration instead of compile-in. Edited May 16, 2014 by sq7bti Quote Link to post Share on other sites
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.