While looking at the schematic for the Keil MCB2130, I noticed that they put a 560K resistor in series with the 32KHz crystal. This seems odd, the only reason I can see for a series resistance is to lower the current through a crystal circuit. Anyone see this? From what I can tell from the LCP2138 manual, only load capacitors are called for to pull the crystal on frequency. AFAICT, my 32KHz crystal is running fine on my board without the series resistor. Look at: http://www.keil.com/mcb2130/mcb2130-schematics.pdf to see what I mean. TomW -- Tom Walsh - WN3L - Embedded Systems Consultant http://openhardware.net, http://cyberiansoftware.com "Windows? No thanks, I have work to do..." ----------------------------------------------------
Message
KEIL MCB2130 RTC clock question
2005-11-02 by Tom Walsh