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ADuC848 Crystal

Question asked by sandeepjain on Nov 21, 2012
Latest reply on Nov 22, 2012 by AudeR
Branched from an earlier discussion

Hi EckartH,


This is Sandeep Jain from Arrow Electronics, One of my customer facing problem on ADUC848.

pls find below details on same and advice solution

We use Analog Devices make ADuC848 BSZ62-5 (52 Lead MQFP) microcontroller in the controller unit of the rectifier. We consume this part in the range 1.2K to 1.5K per anum. Recently, we have face some technical issue in this when using in one of our product. After root cause analysis of the problem, we came to know that there is error in the timing calculated by the controller and the real time clock. The error is 1 minute in 1 hour. Initially we thought that this is related to the crystal of 32.768KHz connected externally to XTAL1 and XTAL2 pins of the microcontroller. But after changing the crystal 3-4 times, we found the problem as it is. Then we removed the external crystal from the board and found that the microcontroller is still running well but with the error in the timing. After all this analysis, we concluded that the microcontroller is actually not detecting the external crystal and running on internal clock. The configuration of ports in the product is as below -

PORT 0 : Digital I/Os and LCD display control lines

PORT 1 : Analog Inputs

PORT 2 : Keypad 8 lines for external interface

PORT 3 : Rx, Tx for communication with PC, 4 LCD data lines and 2 digital inputs

Now I have some questions as below -

  1. 1.       Why the controller is not detecting the external crystal?
  2. 2.       How can I check and ensure that the external port pins of the microcontroller (hardware) are OK or not?
  3. 3.       Is this related to corruptions of flash memory of microcontroller? If it is so, what can be the cause behind that?