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NUC970 Technical Reference Manual
Publication Release Date: Dec. 15, 2015
- 539 -
Revision V1.30
NUC97
0
T
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CHNIC
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NUA
L
mw_ss_o
mw_sclk_o
mw_so_o
mw_si_i
CNTRL[LSB]=1, CNTRL[Tx_NUM]=0x0, CNTRL[Tx_BIT_LEN]=0x08,
CNTRL[Tx_NEG]=0, CNTRL[Rx_NEG]=1, SSR[SS_LVL]=0
MSB
(Tx[7])
LSB
(Tx[0])
MSB
(Rx[7])
LSB
(Rx[0])
Tx[1]
Tx[2]
Tx[3]
Tx[4]
Tx[5]
Tx[6]
Rx[1]
Rx[2]
Rx[3]
Rx[4]
Rx[5]
Rx[6]
Figure 5.19-3 Alternate Phase SCLK Clock Timing
Dual and Quad IO Mode
5.19.5.3
This SPI controller also supports dual and quad IO transfer for SPI Flash when set the DUALM or
QUAD bit (CNTRL[21:20]) to 1. The DIR_2QM bit (CNTRL[20]) is used to define the direction of the
transfer data. When set the DIR_2QM bit to 1, the controller will send the data to external device.
When the DIR_2QM bit set 0, the controller will read the data from the external device. This function
supports 8, 16, 24, and 32-bits of bit length.
If both the DUALM (or QUADM) and DIR_2QM bits are set as 1, the mw_so_o[0] is the lowest bit data
output and the mw_so_o[1] (or mw_so_o[3]) will be set as the uppermost bit data output. If the
DUALM (or QUADM) is set as 1 and DIR_2QM is set as 0, both the mw_si_i will be set as data input
ports. The following Figure shows the dual IO function timing diagram. The Quad mode timing is
similar to the dual IO mode.
Figure 5.19-4 Dual-IO output Sequence
SS
SCL
K
mw_so_o[0]
(Output)
mw_so_o[1]
(Output)
DUALM
DIR_2QM