SH7262 datasheet(14/45 Pages) RENESAS

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SH7262/SH7264 Group

High-speed Read/Write Serial Flash Memory

Using the Renesas Serial Peripheral Interface

REJ06B0889-0100/Rev.1.00

June 2009

Page 14 of 45

2.4.2

Command Transfer Example

The sample program supports two types of command, the Read command that uses both the master output and slave output,

and the Write command that uses the master output only. Figure 11 to Figure 13 show the flow charts of the read command

transfer. The access width when reading data is specified in longword (32-bit). Use the DMA transfer to store data in

memory.

Figure 14 shows the flow chart of the write command transfer. As the busy time is longer than the time to transfer

commands, the access width is specified in byte-wide in this example.

Read command transfer

Transferred

all commands?

Yes

• Transfer data (opcode and address bytes for the command sequence) output

by the master. Five bytes in total (opcode 0x0B, three bytes address, and

dummy byte) are transferred when the Read Array is issued.

• Command size must be equal or less than eight bytes to avoid the transmit

FIFO overflow.

Reset the transmit/receive buffers

Enable the SPI to transfer data

• Set the SPCR register (SPE bit = 1)

Function: Enable the RSPI

(This register enables the RSPI transfer function.)

• Set the SPBFCR register (SPBFCR = 0xC0, SPBFCR = 0x00)

Function: Reset the data in the transmit/receive buffers

(It should be cleared to 0 every time the data is written.)

Write command in the Data register

Wait for the transfer end

Reset the transmit/receive buffers

Extend the setup time for MOSI

direction (Master to Slave)

• Set the SPCMD register (CPOL bit = 1, CPHA bit = 0)

Functions:

(1) Specify the RSPCK when idling as 1

(2) Specify the RSPCK to output data on even edge

Extend the setup time for MISO

direction (Slave to Master)

• Set the SPCMD register (CPOL bit = 0, CPHA bit = 1)

Functions:

(1) Specify the RSPCK when idling as 0

(2) Latch data on odd edge

Extend the access width to longword

• Set the SPDCR register (SPLW bit = 3)

Function: Specify the access width to the SPDR register as 32-bit

• Set the SPCMD register (SPB bit = 3)

Function: Specify the transfer data length as 32-bit

Figure 11 Flow Chart of the Read Command Transfer (1/3)

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