Hi all,
I am developing on Keil uVision v4.74 for LPC2478 controller and using Keil ULinkPro for debugging.
Having problems lately while debugging on target board with ULinkPro. Our code uses UART1 interface and having some specific registers like U1LSR(Line Status Register) and U1FCR(Fifo Control Register) that we use directly. Those are declared volatile in the LPC24XX.h coming with keil compiler installation.
In Debug mode, we have put those 2 registers in Watch window. At the same time we are also having the Memory window with the address of those registers. While single stepping the code at the same statement where we are reading those Registers, we see different values in Watch window and in Memory window. On mouse hovering that register, we see the same value as Memory value.
Why the 2 different views are showing different value for the same memory address?
Regards, Girish Thavai
Most likely because that's not memory. It's a hardware register. Its value can change all by itself, every time you read it. Some registers are clear-on-read, i.e. they will change because you read them.
Using memory or watches to inspect this kind of register is generally a bad idea.
Got it. Thanks.