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
Document Number: MCF51JM128
Rev. 2, 09/2008
Thanks in advance for any help as otherwise we have to bury this chip.