UM10429
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User manual
Rev. 1 — 20 October 2010
93 of 258
NXP Semiconductors
UM10429
Chapter 11: LPC1102 SPI0 with SSP
11.6.2 SPI/SSP0 Control Register 1
This register controls certain aspects of the operation of the SPI/SSP controller.
5:4
FRF
Frame Format.
00
0x0
SPI
0x1
TI
0x2
Microwire
0x3
This combination is not supported and should not be used.
6
CPOL
Clock Out Polarity. This bit is only used in SPI mode.
0
0
SPI controller maintains the bus clock low between frames.
1
SPI controller maintains the bus clock high between frames.
7
CPHA
Clock Out Phase. This bit is only used in SPI mode.
0
0
SPI controller captures serial data on the first clock transition
of the frame, that is, the transition
away from
the inter-frame
state of the clock line.
1
SPI controller captures serial data on the second clock
transition of the frame, that is, the transition
back to
the
inter-frame state of the clock line.
15:8
SCR
Serial Clock Rate. The number of prescaler-output clocks per
bit on the bus, minus one. Given that CPSDVSR is the
prescale divider, and the APB clock PCLK clocks the
prescaler, the bit frequency is PCLK / (CPSDVSR
×
[SCR+1]).
0x00
31:16 -
-
Reserved
-
Table 91:
SPI/SSP Control Register 0 (SSP0CR0 - address 0x4004 0000) bit description
Bit
Symbol
Value
Description
Reset
Value
Table 92:
SPI/SSP Control Register 1 (SSP0CR1 - address 0x4004 0004) bit description
Bit
Symbol
Value
Description
Reset
Value
0
LBM
Loop Back Mode.
0
0
During normal operation.
1
Serial input is taken from the serial output (MOSI or MISO)
rather than the serial input pin (MISO or MOSI
respectively).
1
SSE
SPI Enable.
0
0
The SPI controller is disabled.
1
The SPI controller will interact with other devices on the
serial bus. Software should write the appropriate control
information to the other SPI/SSP registers and interrupt
controller registers, before setting this bit.