How to use System Viewer to check register status and modify the setting?

[a_ziliu]

Function:
System Viewer is a helpful tool to check register status in KEIL debug mode
(1) Monitors register value in real-time
(2) Changes register value and becomes effective immediately
Scenario:
(1) When peripheral does not work as user expected, System Viewer can help user to monitor the register.
(2) User wants to change the setting of the register and does not want to reprogram and rebuild code.
Use System Viewer to check register status :
(1) “Alt + F7” open “Options for Target”, and select “Target” dialog.
(2) Check if the default SFR file is for the target chip. SFR file can be selectable by enable “Use Custom File”

(3) Enter debug mode
(4) Select the peripheral from tool bar. There are three ways for select the tool bar.
a. Peripherals/System Viewer

b. Icon

c. View/System Viewer

(5) Find the register that user wants to check and modify. Frame will be highlighted in green when value changed. Ex. HCLKSEL

(6) Select another setting of register HCLKSEL

(7) The HCLK register has modified to option 3 – Clock source from LIRC.