Serge Luternauer

MCF51JM128 44 LQFP Pinout

Discussion created by Serge Luternauer on Jul 9, 2009
Latest reply on Aug 29, 2009 by kef

We started to explore the MCF51JM128 in the 44 LQFP package in a first design. First steps with this familiy we did with the DEMOJM Evaluation Board which comes with a MCF51JM128 module in the 64 LQFP package. By testing our design with the 44 LQFP package we saw, that the clock circuit (6MHz Crystal, 22pF, with and/or without Rf=1MOhm & Rs=10Ohm) did not work at all. Additionnally the RESET pin delivered a perfect about 20kHZ square wave which we didn't get away even with 10kOhm Pullup and 100nF Pulldown as recommended in the referende manual. We tested it with a new chip, same results. Then again with a new chip we build a flying circuit with VSS(5V),VDD,RESET(10k/100nF) and BKGD(10k pullup) connected and a crystal clock circuit on EXTAL/XTAL as described above. Same results, the EXTAL/XTAL pins showed a pure ground line on the oscilloscope. Then we cutted our flying circuit from the 44 LQFP package and connected it to the 64LQFP module from our DEMOJM evaluation board. Result: It works!, no more square wave out of the RESET pin and a clear clock at the XTAL pins. So our question is: Do we have 3 defect chip (new samples from our distributor) or is the pinout for the 44 LQFP package given in the datasheet


MCF51JM128 ColdFire


Document Number: MCF51JM128

Rev. 2, 09/2008


wrong ?


Thanks in advance for any help as otherwise we have to bury this chip.