R5F52107ADFN datasheet(32/92 Pages) RENESAS

32 / 92 page

R01DS0041EJ0050 Rev.0.50

Page 32 of 90

Apr 15, 2011

RX210 Group

2. CPU

Under development Preliminary document

Specifications in this document are tentative and subject to change.

The processor status word (PSW) indicates the results of instruction execution or the state of the CPU.

C Flag (Carry Flag)

This flag indicates whether a carry, borrow, or shift-out has occurred as the result of an operation.

Z Flag (Zero Flag)

This flag indicates that the result of an operation was 0.

S Flag (Sign Flag)

This flag indicates that the result of an operation was negative.

O Flag (Overflow Flag)

This flag indicates that an overflow occurred during an operation.

I Bit (Interrupt Enable)

This bit enables interrupt requests. When an exception is accepted, the value of this bit becomes 0.

U Bit (Stack Pointer Select)

This bit specifies the stack pointer as either the ISP or USP. When an exception request is accepted, this bit is set to 0.

When the processor mode is switched from supervisor mode to user mode, this bit is set to 1.

PM Bit (Processor Mode Select)

This bit specifies the processor mode. When an exception is accepted, the value of this bit becomes 0.

IPL[3:0] Bits (Processor Interrupt Priority Level)

The IPL[3:0] bits specify the processor interrupt priority level as one of sixteen levels from zero to fifteen, wherein

priority level zero is the lowest and priority level fifteen the highest. When the priority level of a requested interrupt is

higher than the processor interrupt priority level, the interrupt is enabled. Setting the IPL[3:0] bits to level fifteen (Fh)

disables all interrupt requests. The IPL[3:0] bits are set to level fifteen (Fh) when a non-maskable interrupt is generated.

When interrupts in general are generated, the bits are set to the priority levels of accepted interrupts.

2.2.2.5

Backup PC (BPC)

The backup PC (BPC) is provided to speed up response to interrupts.

After a fast interrupt has been generated, the contents of the program counter (PC) are saved in the BPC register.

b31

Value after reset:

Undefined

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