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we have a problem in using mc9s12hy64 during developping a board, that is our board will reset when using a cellphone to call out,that maybe EMC problem

Question asked by hongjian zhang on Dec 19, 2016
Latest reply on Dec 27, 2016 by hongjian zhang

When we put a cellphone close to our board ,it is likely that the mcu will reset,  but not all the phone can cause this problem, and only when the phone is in calling someone and his phone doesn't have alarm;


our board using  mc9s12hy64 mcu, using outside 8m frequency crystal oscillator, an the software config the mcu using a frequency of 64M ,so the bus clock is 32M , the software config init code as below:


unsigned char i = 255;

CPMUPROT = 0x26;

CPMUREFDIV = 0x80; /* Config fREF 4M */
CPMUSYNR = 0x43; /* Config fVCO 64M */
CPMUPOSTDIV = 0x00; /* Config fPLL 64M fBus 32M */

CPMUOSC_OSCE = 1; /* enable ext OSC */

}while((!CPMUFLG_UPOSC || !CPMUFLG_LOCK) && (i));
/* wait for ext osc to stabilize and pll to lock */
CPMUCLKS = 0x81; /* RTI COP clock source is oscclk */
CPMUCOP = 0x46;

/* watchdog reset time 1.04S */
CPMURTI = 0xF9; /* RTI Time 0.25s */
CPMUINT_RTIE = 0; /* enable RTI interrupt */

while( CPMUCLKS != 0x81 )
CPMUCLKS = 0x81;

CPMUPROT = 0x01; /* Protect pll clock */



Can anyone give an advise or give me some direction?