UM10360 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved.
User manual Rev. 3 — 19 December 2013 423 of 841
NXP Semiconductors
UM10360
Chapter 18: LPC176x/5x SSP0/1
18.6.2 SSPn Control Register 1 (SSP0CR1 - 0x4008 8004, SSP1CR1 -
0x4003 0004)
This register controls certain aspects of the operation of the SSP controller.
Table 370: SSPn Control Register 0 (SSP0CR0 - address 0x4008 8000, SSP1CR0 -
0x4003 0000) bit description
Bit Symbol Value Description Reset
Value
3:0 DSS Data Size Select. This field controls the number of bits
transferred in each frame. Values 0000-0010 are not supported
and should not be used.
0000
0011 4-bit transfer
0100 5-bit transfer
0101 6-bit transfer
0110 7-bit transfer
0111 8-bit transfer
1000 9-bit transfer
1001 10-bit transfer
1010 11-bit transfer
1011 12-bit transfer
1100 13-bit transfer
1101 14-bit transfer
1110 15-bit transfer
1111 16-bit transfer
5:4 FRF Frame Format. 00
00 SPI
01 TI
10 Microwire
11 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 SSP controller maintains the bus clock low between frames.
1 SSP controller maintains the bus clock high between frames.
7 CPHA Clock Out Phase. This bit is only used in SPI mode. 0
0 SSP 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 SSP 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
31:8 - Reserved, user software should not write ones to reserved bits.
The value read from a reserved bit is not defined.
NA
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