15 Quad Synchronous Serial Interface (QSPI)
15-28
Seiko Epson Corporation
S1C31D50/D51 TECHNICAL MANUAL
(Rev. 2.00)
Register access master mode
QSPICLKn
QSDIOn[3:0]
QSPI_nINTF.BSY
QSPI_nINTF.TENDIF
QSPI_nMOD register
1
2
3
4
CPHA bit
1
0
CPOL bit
1
0
Writing data to the QSPI_nTXD register
Slave mode
#QSPISSn
QSPI_nINTF.BSY
QSPICLKn
QSDIOn[3:0]
QSPICLKn
QSDIOn[3:0]
QSPI_nINTF.TENDIF
QSPI_nMOD register
1
2
3
4
CPHA bit
1
0
CPOL bit
1
0
Writing data to the QSPI_nTXD register
Memory mapped access mode
#QSPISSn
QSPICLKn
QSDIOn[3:0]
QSPI_nINTF.MMABSY
#QSPISSn
inactive period
(TCSH)
QSPI_nMOD register
CPHA bit
1
0
CPOL bit
1
0
Address cycle
(high-order 8/16 bits)
Address cycle
(low-order 16 bits)
Dummy cycle
1 (W)
→
QSPI_nMMACFG2.MMAEN
0 (W)
→
QSPI_nMMACFG2.MMAEN
Figure 15.6.1 QSPI_nINTF.BSY, QSPI_nINTF.MMABSY, and QSPI_nINTF.TENDIF Bit Set Timings
(when QSPI_nMOD.CHDL[3:0] bits = QSPI_nMOD.CHLN[3:0] bits = 0x3)
15.7 DMA Transfer Requests
The QSPI has a function to generate DMA transfer requests from the causes shown in Table 15.7.1.
Table 15.7.1 DMA Transfer Request Causes of QSPI
Cause to request
DMA transfer
DMA transfer request flag
Set condition
Clear condition
Receive buffer full Receive buffer full flag
(QSPI_nINTF.RBFIF)
When data of the specified bit length is re-
ceived and the received data is transferred from
the shift register to the received data buffer
Reading of the QSPI_
nRXD register
Transmit buffer
empty
Transmit buffer empty flag
(QSPI_nINTF.TBEIF)
When transmit data written to the transmit data
buffer is transferred to the shift register
Writing to the QSPI_
nTXD register
Memory mapped
access FIFO data
ready
Memory mapped access
FIFO data ready flag
(internal signal)
When a 32-bit data is prefetched into the FIFO
in memory mapped access mode
When the FIFO read
level is cleared to 0