R8CSLASH20 datasheet(408/501 Pages) RENESAS

408 / 501 page

R8C/20 Group, R8C/21 Group

19. Flash Memory

Rev.2.00 Aug 27, 2008

Page 392 of 458

REJ09B0250-0200

19.4.3

Software Commands

Software commands are described below. Read or write commands and data from or to in 8-bit units.

SRD: Status register

data (D7 to D0)

WA: Write address (Ensure the address specified in the first bus cycle is the same address as the write

address specified in the second bus cycle.)

WD: Write data (8 bits)

BA: Given block address

×:

Any specified address in the user ROM area

19.4.3.1

Read Array Command

The read array command reads the flash memory.

The MCU enters read array mode by writing FFh in the first bus cycle. If entering the read address after the

following bus cycles, the content of the specified address can be read in 8-bit units.

Since the MCU remains in read array mode until another command is written, the contents of multiple

addresses can be read continuously.

In addition, the MCU enters read array mode after a reset.

19.4.3.2

Read Status Register Command

The read status register command reads the status register.

If writing 70h in the first bus cycle, the status register can be read in the second bus cycle. (Refer to 19.4.4

Status Registers) When reading the status register, specify an address in the user ROM area.

Do not execute this command in EW1 mode.

The MCU remains in read status register mode until the next read array command is written.

19.4.3.3

Clear Status Register Command

The clear status register command sets the status register to 0.

If writing 50h in the first bus cycle, the FMR06 to FMR07 bits in the FMR0 register and SR4 to SR5 in the

status register will be set to 0.

Table 19.4

Software Commands

Command

First Bus Cycle

Second Bus Cycle

Mode

Address

Data

(D7 to D0)

Mode

Address

Data

(

D7 to D0)

Read Array

Write

FFh

Read Status Register

Write

70h

Read

SRD

Clear Status Register

Write

50h

Program

Write

40h

Write

Block Erase

Write

20h

Write

D0h

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