15 Quad Synchronous Serial Interface (QSPI)
15-18
Seiko Epson Corporation
S1C31D50/D51 TECHNICAL MANUAL
(Rev. 2.00)
If an address in the memory mapped access area that is not continuous to the previous read address is read, the
HREADY signal is pulled down to low immediately and the FIFO read level is cleared to 0 (empty status). The
#QSPISS
n
signal is negated once for the period set in the QSPI_
n
MMACFG1.TCSH[3:0] bits and then asserted
again. After that a new address cycle, dummy cycle, and data cycle are executed.
The beginning and the end of each address, dummy, or data cycle take a couple of HCLK clocks for handshak-
ing.
n
2
2
0
HCLK
HSEL
HADDR
HTRANS
HSIZE
HREADY
HRDATA
fifo_read_level
QSPICLKn
QSDIOn[3:0]
Address cycle
(high-order 8/16 bits)
Address cycle
(low-order 16 bits)
Dummy
cycle
QSPI_nMOD register
CPHA bit
1
0
CPOL bit
1
0
0
1
0
1
n
HCLK
HSEL
HADDR
HTRANS
HSIZE
HREADY
HRDATA
fifo_read_level
QSPICLKn
QSDIOn[3:0]
Dummy cycle
Data cycle 2
(prefetching)
Data cycle 3
(prefetching)
QSPI_nMOD register
CPHA bit
1
0
CPOL bit
1
0
2
Data cycle 1
Figure 15.5.6.1 Data Receiving Operation in Memory Mapped Access Mode - First 32-bit Read