15 Quad Synchronous Serial Interface (QSPI)
S1C31D50/D51 TECHNICAL MANUAL
Seiko Epson Corporation
15-15
(Rev. 2.00)
QSPICLKn
QSDIOn[3:0]
QSPI_nINTF.TBEIF
QSPI_nINTF.RBFIF
QSPI_nINTF.TENDIF
Software operations
Data (W)
→
QSPI_nTXD
Data (W)
→
QSPI_nTXD
Data (W)
→
QSPI_nTXD
QSPI_nRXD
→
Data (R)
1 (W)
→
QSPI_nINTF.TENDIF
QSPI_nRXD
→
Data (R)
QSPI_nRXD
→
Data (R)
1
2
3
4
1
2
3
4
1
2
3
4
Figure 15.5.5.1 Example of Data Receiving Operations in Register Access Master Mode
(QSPI_nMOD.CHDL[3:0] bits = QSPI_nMOD.CHLN[3:0] bits = 0x3)
Data reception
End
Read the QSPI_nINTF.TBEIF bit
Write dummy data (or transmit data) to
the QSPI_nTXD register
Read receive data from
the QSPI_nRXD register
YES
NO
NO
YES
Receive data remained?
QSPI_nINTF.TBEIF = 1 ?
Wait for an interrupt request
(QSPI_nINTF.RBFIF = 1)
(A) Intermittent data reception
Data reception
End
Read the QSPI_nINTF.TBEIF bit
Write dummy data (or transmit data) to
the QSPI_nTXD register
Read receive data from
the QSPI_nRXD register
YES
NO
NO
YES
Receive data remained?
QSPI_nINTF.TBEIF = 1 ?
Wait for an interrupt request
(QSPI_nINTF.TBEIF = 1)
(B) Continuous data reception
Write dummy data (or transmit data) to
the QSPI_nTXD register
Wait for an interrupt request
(QSPI_nINTF.RBFIF = 1)
Execute this sequence
within the QSPICLKn
cycles equivalent to
“Data bit length - 1” from
an interrupt request
Assert the slave select signal output from
the #QSPISSn pin (QSPI_nCTL.MSTSSO
= 0) or a general-purpose port
(
)
Assert the slave select signal output from
the #QSPISSn pin (QSPI_nCTL.MSTSSO
= 0) or a general-purpose port
(
)
Negate the slave select signal output from
the #QSPISSn pin (QSPI_nCTL.MSTSSO
= 1) or a general-purpose port
(
)
Negate the slave select signal output from
the #QSPISSn pin (QSPI_nCTL.MSTSSO
= 1) or a general-purpose port
(
)
Set the transfer direction to input
(QSPI_nCTL.DIR = 1)
Not necessary
in single
transfer mode
Set the transfer direction to input
(QSPI_nCTL.DIR = 1)
Not necessary
in single
transfer mode
Figure 15.5.5.2 Data Reception Flowcharts in Register Access Master Mode
Data reception using DMA
For data reception, two DMA controller channels should be used to write dummy data to the QSPI_
n
TXD reg-
ister as a reception start trigger and to read the received data from the QSPI_
n
RXD register.
By setting the QSPI_
n
TBEDMAEN.TBEDMAEN
x
1
bit to 1 (DMA transfer request enabled), a DMA transfer
request is sent to the DMA controller and dummy data is transferred from the specified memory to the QSPI_
n
TXD register via DMA Ch.
x
1
when the QSPI_
n
INTF.TBEIF bit is set to 1 (transmit buffer empty).