Programmer’s Reference

4.3.8Flag registers, SYS_FLAGx and SYS_NVFLAGx

The registers shown in Table 4-10 provide two 32-bit register locations containing general-purpose flags. You can assign any meaning to the flags.

 

 

 

 

Table 4-10 Flag registers

 

 

 

 

 

Register name

Address

Access

Reset by

Description

 

 

 

 

 

SYS_FLAGS

0x10000030

Read

Reset

Flag register

 

 

 

 

 

SYS_FLAGSSET

0x10000030

Write

Reset

Flag Set register

 

 

 

 

 

SYS_FLAGSCLR

0x10000034

Write

Reset

Flag Clear register

 

 

 

 

 

SYS_NVFLAGS

0x10000038

Read

POR

Nonvolatile Flag register

 

 

 

 

 

SYS_NVFLAGSSET

0x10000038

Write

POR

Nonvolatile Flag Set register

 

 

 

 

 

SYS_NVFLAGSCLR

0x1000003C

Write

POR

Nonvolatile Flag Clear register

 

 

 

 

 

The PB926EJ-S provides two distinct types of flag registers:

The SYS_FLAGS Register is cleared by a normal reset, such as a reset caused by pressing the reset button.

The SYS_NVFLAGS Register retains its contents after a normal reset and is only cleared by a Power-On Reset (POR).

Flag and Nonvolatile Flag Registers

The SYS_FLAGS and SYS_NVFLAGS registers contain the current state of the flags.

Flag and Nonvolatile Flag Set Registers

The SYS_FLAGSSET and SYS_NVFLAGSSET registers are used to set bits in the

SYS_FLAGS and SYS_NVFLAGS registers:

write 1 to SET the associated flag

write 0 to leave the associated flag unchanged.

Flag and Nonvolatile Flag Clear Registers

Use the SYS_FLAGSCLR and SYS_NVFLAGSCLR registers to clear bits in

SYS_FLAGS and SYS_NVFLAGS:

write 1 to CLEAR the associated flag

write 0 to leave the associated flag unchanged.

4-30

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ARM DUI 0224I

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ARM ARM DUI 0224I manual Flag registers, SYSFLAGx and SYSNVFLAGx, Flag and Nonvolatile Flag Registers