15 Quad Synchronous Serial Interface (QSPI)
S1C31D50/D51 TECHNICAL MANUAL
Seiko Epson Corporation
15-13
(Rev. 2.00)
QSPICLKn
QSDIOn[3:0]
QSPI_nINTF.TBEIF
QSPI_nINTF.TENDIF
Software operations
1
2
3
4
1
2
3
4
1
2
3
4
Data (W)
→
QSPI_nTXD
Data (W)
→
QSPI_nTXD
1 (W)
→
QSPI_nINTF.TENDIF
Data (W)
→
QSPI_nTXD
Figure 15.5.4.1 Example of Data Sending Operations in Master Mode
(QSPI_nMOD.CHDL[3:0] bits = QSPI_nMOD.CHLN[3:0] bits = 0x3)
Data transmission
End
Negate the slave select signal output from
the #QSPISSn pin (QSPI_nCTL.MSTSSO
= 1) or a general-purpose port
Assert the slave select signal output from
the #QSPISSn pin (QSPI_nCTL.MSTSSO
= 0) or a general-purpose port
(
)
(
)
Read the QSPI_nINTF.TBEIF bit
Set the transfer direction to output
(QSPI_nCTL.DIR = 0)
Write transmit data to
the QSPI_nTXD register
YES
NO
Not necessary
in single transfer mode
NO
YES
Transmit data remained?
QSPI_nINTF.TBEIF = 1 ?
Wait for an interrupt request
(QSPI_nINTF.TBEIF = 1)
Figure 15.5.4.2 Data Transmission Flowchart in Master Mode
Data transmission using DMA
By setting the QSPI_
n
TBEDMAEN.TBEDMAEN
x
bit to 1 (DMA transfer request enabled), a DMA transfer
request is sent to the DMA controller and transmit data is transferred from the specified memory to the QSPI_
n
TXD register via DMA Ch.
x
when the QSPI_
n
INTF.TBEIF bit is set to 1 (transmit buffer empty).
This automates the procedure from Step 3 to Step 6 described above.
The transfer source/destination and control data must be set for the DMA controller and the relevant DMA
channel must be enabled to start a DMA transfer in advance so that transmit data will be transferred to the
QSPI_
n
TXD register. For more information on DMA, refer to the “DMA Controller” chapter.