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XS128 serial flash programming error.

Question asked by Padelis Floudas on Nov 29, 2014
Latest reply on Nov 30, 2014 by Padelis Floudas



i am working on a serial bootloader for which i dont have the original source code but i can debug it in Codewarrior with USBBDM.

The problem is when it reaches a certain point in the code. In sort it loads 0xF at GPAGE and then it stores a word or byte at the specified location.

On the GSTD or GSTAB instruction the cpu resets. So i have to start from the beginning. Here is the code in assemble language.


ORCC     #0X10 LDAB     0x10 PSHB MOVB     #0xF, 0x0010 LDX     0x300E LDD     0x3010 GSTD     0x0, X PULB STAB     0x10 ANDCC #0xEF RTS


The cpu resets at the GSTD instruction.

A sort explanation on what the above code does is this,

Store 0xF to GPAGE

Load target address in X and word in D

Save word D at 0xF_xxxx.


Can someone suggest something or have an idea on what is going wrong here?

I would expect that the 0xF_3000 is the "global" ram location which is the same as the "logical" ram location which is at 0x3000.