38K2 datasheet(124/358 Pages) RENESAS

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FUNCTIONAL DESCRIPTION

Rev.2.00

Oct 15, 2006

page 105 of 130

38K2 Group

REJ09B0338-0200

HARDWARE

Software Commands

Table 10 lists the software commands.

After setting the CPU Rewrite Mode Select Bit to “1”, write a soft-

ware command to specify an erase or program operation.

Each software command is explained below.

qRead Array Command (FF16)

The read array mode is entered by writing the command code

“FF16” in the first bus cycle. When an address to be read is input in

one of the bus cycles that follow, the contents of the specified ad-

dress are read out at the data bus (D0 to D7).

The read array mode is retained intact until another command is

written.

qRead Status Register Command (7016)

When the command code “7016” is written in the first bus cycle,

the contents of the status register are read out at the data bus (D0

to D7) by a read in the second bus cycle.

The status register is explained in the next section.

qClear Status Register Command (5016)

This command is used to clear the bits SR4 and SR5 of the status

tion has ended in an error. To use this command, write the

command code “5016” in the first bus cycle.

qProgram Command (4016)

Program operation starts when the command code “4016” is writ-

ten in the first bus cycle. Then, if the address and data to program

are written in the 2nd bus cycle, the control circuit of flash memory

(data programming and verification) will start a program.

Whether the write operation is completed can be confirmed by

_____

reading the status register or the RY/BY Status Flag. When the

program starts, the read status register mode is entered automati-

cally and the contents of the status register is read at the data bus

(DB0 to DB7). The status register bit 7 (SR7) is set to “0” at the

same time the write operation starts and is returned to “1” upon

completion of the write operation. In this case, the read status reg-

ister mode remains active until the read array command (FF16) is

written.

Table 10 List of software commands (CPU rewrite mode)

____

During the program movement, The RY/BY Status Flag of flash

memory control register is set to “0”. When the program com-

pletes, it becomes “1”.

At program end, program results can be checked by reading the

status register.

Fig. 149 Program flowchart

Command

Program

Clear status register

Read array

Read status register

First bus cycle

Second bus cycle

FF16

7016

5016

4016

Write

SRD

Read

Write

Erase all blocks

2016

Write

2016

Write

(Note 1)

WA (Note 2)

WD (Note 2)

Block erase

2016

Write

D016

Write

BA (Note 3)

Mode

Address

Mode

Address

Data

(D0 to D7)

(Note 4)

Notes 1: SRD = Status Register Data

2: WA = Write Address, WD = Write Data

3: BA = Block Address to be erased (Input the maximum address of each block.)

4: X denotes a given address in the User ROM area .

Cycle number

Data

Start

Write 4016

Status register

read

Program

completed

YES

Write address

Write data

SR4 = 0 ?

Program

error

YES

SR7 = 1 ?

RY/BY = 1 ?

Write

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