Aric Lowe

JM128 Pins not operating correctly

Discussion created by Aric Lowe on Mar 13, 2009
Latest reply on Mar 13, 2009 by Aric Lowe

Hello everyone,

 

Id appreciate any advice I can on a little problem Im experiencing with the JM128 chip.  Im currently interfacing to an external SRAM chip with the JM128.  The problem that Im having is when I set the address on the pins ( Most sig. byte port D, Mid sig. Port E, and least sig. byte Port F).  I need to use 3 ports to address 500K spaces.  The problem however is within Port E pins 0 and 1.  The rest of the pins are set correctly however Port E pin 0 is ALWAYS high, and Port E pin 1 sits at about 1.5 V regardless of what I set them at.  Obvisouly this posses a significant problem in addressing a specific memory address when two of the middle bits are consistently erraneous.  Im not using any of these pins for any other function of that this and have not enabled any serial communication that these two pins could potentially be used for.  Any thoughts out there from the great Freescale Masters??

 

Thanks,

 

Aric

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