15-6
Seiko Epson Corporation
S1C31D50 TECHNICAL MANUAL
(Rev. 1.00)
15.2.3.
Pin Functions in Master Mode and Slave Mode
The pin functions are changed according to the transfer direction, transfer mode, and master/slave
mode selections. The differences in pin functions between the modes are shown in Table 15.2.3.1.
Table 15.2.3.1 Pin Function Differences between Modes
Pin
Function in master mode
Function in slave mode
Single transfer mode Dual transfer
mode
Quad transfer
mode
Single transfer mode Dual transfer
mode
Quad transfer
mode
QSDIO
n
[3:2]
Always placed into Hi-Z state.
T h e s e p i n s a r e
placed
into
input or out pu t
s t a t e according
to
the
QSPI_
n
CTL.DIR bit
setting.
Always placed into Hi-Z state.
T h e s e p i n s a r e
placed
into
output
state
while
a
low
leve l is a pplied
to the #QSPISS
n
pin and the QSPI_
n
CTL.DIR bit is set
to 0 (output),
or placed into
Hi-Z state while
a high level is
applied to the
#QSPISS
n
pin or
the
QSPI_
n
CTL.
DIR bit is set to 1
(input).
QSDIO
n
1
Always
placed
into input state.
T h e s e p i n s a r e
placed
into
input or o ut pu t
s t a t e according
to
the
QSPI_
n
CTL.DIR bit
setting.
Always
placed
into input state.
T h e s e p i n s a r e
placed
into
output
state
while
a
low
leve l is a pplied
to the #QSPISS
n
pin and the QSPI_
n
CTL.DIR bit is set
to 0 (output),
or placed into
Hi-Z state while
a high level is
applied to the
#QSPISS
n
pin or
the
QSPI_
n
CTL.
DIR bit is set to 1
(input).
QSDIO
n
0
Always
placed
into output state.
This pin is placed
into output state
while
a
low
level is applied
to the
#QSPISS
n
pin or
placed into Hi-Z
state while a
high level
is
applied to the
#QSPISS
n
pin.
QSPICLK
n
Outputs the QSPI clock to external devices.
Output clock polarity and phase can be configured if nec-
essary.
Inputs an external QSPI clock.
Clock polarity and phase can be designated according to
the input clock.
#QSPISS
n
This pin is used to output the slave select signal in mas-
ter mode. In memory mapped access mode, this pin is
controlled by the internal state machine. In register ac-
cess mode, this pin is controlled by a register bit. When
connecting more than one external slave device, general-
purpose I/O ports can be used to output the extra slave
select signals.
Applying a low level to the #QSPISS
n
pin enables the
QSPI to transmit/receive data. While a high level is applied
to this pin, the QSPI is not selected as a slave device. Data
input to the QSDIO
n
pins and the clock input to the QSPI-
CLK
n
pin are ignored. When a high level is applied, the
transmit/receive bit count is cleared to 0 and the already
received bits are discarded.
15.2.4.
Input Pin Pull-Up/Pull-Down Function
The QSPI pins (QSDIO
n
[3:0] pins in master mode or QSDIO
n
[3:0] pins, QSPICLK
n
, and #QSPISS
n
pins in
slave mode) have a pull-up or pull-down function as shown in Table 15.2.4.1. This function is enabled
by setting the QSPI_
n
MOD.PUEN bit to 1.
Table 15.2.4.1 Pull-Up or Pull-Down of QSPI Pins
Pin
Master mode
Slave mode
QSDIO
n
[3:0]
Pull-up
Pull-up
QSPICLK
n
–
QSPI_
n
MOD.CPOL bit = 1: Pull-up
QSPI_
n
MOD.CPOL bit = 0: Pull-down
#QSPISS
n
–
Pull-up
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