SH7713 datasheet(67/904 Pages) RENESAS

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Section 2 CPU

CPUS3D0S_000020020300

Rev.1.50 Aug. 30, 2006 Page 27 of 860

REJ09B0288-0150

Section 2 CPU

2.1

Processing States and Processing Modes

2.1.1

Processing States

This LSI supports four types of processing states: a reset state, an exception handling state, a

program execution state, and a low-power consumption state, according to the CPU processing

states.

Reset State: In the reset state, the CPU is reset. The LSI supports two types of resets: power-on

reset and manual reset. For details on resets, refer to section 4, Exception Handling.

In power-on reset, the registers and internal statuses of all LSI on-chip modules are initialized. In

manual reset, the register contents of a part of the LSI on-chip modules, such as the bus state

controller (BSC), are retained. For details, refer to section 23, List of Registers. The CPU internal

statuses and registers are initialized both in power-on reset and manual reset. After initialization,

the program branches to address H'A0000000 to pass control to the reset processing program to be

executed.

Exception Handling State: In the exception handling state, the CPU processing flow is changed

temporarily by a general exception or interrupt exception processing. The program counter (PC)

and status register (SR) are saved in the save program counter (SPC) and save status register

(SSR), respectively. The program branches to an address obtained by adding a vector offset to the

vector base register (VBR) and passes control to the exception processing program defined by the

user to be executed. For details on reset, refer to section 4, Exception Handling.

Program Execution State: The CPU executes programs sequentially.

Low-Power Consumption State: The CPU stops operation to reduce power consumption. The

low-power consumption state can be entered by executing the SLEEP instruction. For details on

the low-power consumption state, refer to section 10, Power-Down Modes.

Figure 2.1 shows a status transition diagram.

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