X X4ce New Member Aug 19, 2006 #1 hey! Im interfacing 16F877A with PCF8583 to display time on 7Seg. I've used Nigel Tutorial #6 (I2C Board) but i didnt find any 32KHz but 32.768KHz with 20pf capacitor. But my clock is running really fast, its counts 1min in just 25sec. Do i need to use 32KHz? But i didnt find it anywhere in local market. Then i used capacitor trimmer and tunned it but time elapsed at the same rate or not at all. Please help i need to submit this project in 3 days. thanks in advance X4ce
hey! Im interfacing 16F877A with PCF8583 to display time on 7Seg. I've used Nigel Tutorial #6 (I2C Board) but i didnt find any 32KHz but 32.768KHz with 20pf capacitor. But my clock is running really fast, its counts 1min in just 25sec. Do i need to use 32KHz? But i didnt find it anywhere in local market. Then i used capacitor trimmer and tunned it but time elapsed at the same rate or not at all. Please help i need to submit this project in 3 days. thanks in advance X4ce
eblc1388 Active Member Aug 19, 2006 #2 Rest assure that by 32KHz crystal, it always refer to a crystal operating at 32.768KHz, the frequency which is also 2 raised to the fifteen power. When divided by 2^15, this give one pulse per second. You will be searching for days if not weeks for an exactly 32KHz crystal. But my clock is running really fast, its counts 1min in just 25sec. Click to expand... Most probably programming error and nothing to do with the crystal.
Rest assure that by 32KHz crystal, it always refer to a crystal operating at 32.768KHz, the frequency which is also 2 raised to the fifteen power. When divided by 2^15, this give one pulse per second. You will be searching for days if not weeks for an exactly 32KHz crystal. But my clock is running really fast, its counts 1min in just 25sec. Click to expand... Most probably programming error and nothing to do with the crystal.
X X4ce New Member Aug 19, 2006 #3 my i2c baud rate is 100kbps and my bus pullups are 12Kohm, is dat the probelm? Last edited: Aug 20, 2006
X X4ce New Member Aug 20, 2006 #4 i got it working, crystal was bad i replaced it by a 32768 crystal which i got from mouse