Hi, I am using uVision2 with EPM900 for a LPC930 device in Win2K enivronment. However, I have downloaded the lpc900_072004.exe and make use of the LPC9xx examples and start900.A51 file in the uVision2 IDE. The simulator and emulator is found to be behaving differently for this attached piece of code in the timer isr. At first isr is being called, key_ptr is entered a 2 instead of 1 for emulator enivronment. For simulator, key_ptr is entered as 1 (which is correct). Details of emulation: x is a local variable and uses R7. key_ptr is a global. When timer isr is first entered, x is 0. At line L1, x is incremented to 1. At L2, x is still 1 as observed through stepping. At L3, R7 becomes 2 for no apparent reason, and key_ptr is found to be 2 as well!!! Details of simulation: Same as above except when L3 is being executed, there is no change in thge R7 and key_ptr is correctly entered as 1!!! ================= L1: x=x+1; L2: if(x>=0x05) x=ZERO; L3: key_ptr=x; ================= Anyone any ideas?
"Why would x start out as zero? You don't show any initialization, so odds are you don't initialize it to anything. In other words, you're looking at the movement pattern of random garbage." This is a common area where simulation & real-life often differ: Simulators do often initialise their simulated memory to all zeros; if your code relies upon this, it is likely to break when you put it into real hardware where initial memory values are random!