Atmel Evaluation Kit for AT32uC3A0512, 32-Bit AVR Microcontroller Atmel ATEVK1105 ATEVK1105 数据表
产品代码
ATEVK1105
217
AT32UC3A
23.8.9
SPI Chip Select Register
Name:
CSR0... CSR3
Access Type:
Read/Write
• CPOL: Clock Polarity
0 = The inactive state value of SPCK is logic level zero.
1 = The inactive state value of SPCK is logic level one.
CPOL is used to determine the inactive state value of the serial clock (SPCK). It is used with NCPHA to produce the
1 = The inactive state value of SPCK is logic level one.
CPOL is used to determine the inactive state value of the serial clock (SPCK). It is used with NCPHA to produce the
required clock/data relationship between master and slave devices.
• NCPHA: Clock Phase
0 = Data is changed on the leading edge of SPCK and captured on the following edge of SPCK.
1 = Data is captured on the leading edge of SPCK and changed on the following edge of SPCK.
NCPHA determines which edge of SPCK causes data to change and which edge causes data to be captured. NCPHA is
1 = Data is captured on the leading edge of SPCK and changed on the following edge of SPCK.
NCPHA determines which edge of SPCK causes data to change and which edge causes data to be captured. NCPHA is
used with CPOL to produce the required clock/data relationship between master and slave devices.
• CSNAAT: Chip Select Not Active After Transfer
0 = The Peripheral Chip Select Line rises as soon as the last transfer is acheived
1 = The Peripheral Chip Select Line rises after every transfer
CSNAAT can be used to force the Peripheral Chip Select Line to go inactive after every transfer. This allows successful
1 = The Peripheral Chip Select Line rises after every transfer
CSNAAT can be used to force the Peripheral Chip Select Line to go inactive after every transfer. This allows successful
interfacing to SPI slave devices that require this behavior.
• CSAAT: Chip Select Active After Transfer
0 = The Peripheral Chip Select Line rises as soon as the last transfer is achieved.
1 = The Peripheral Chip Select does not rise after the last transfer is achieved. It remains active until a new transfer is
1 = The Peripheral Chip Select does not rise after the last transfer is achieved. It remains active until a new transfer is
requested on a different chip select.
• BITS: Bits Per Transfer
The BITS field determines the number of data bits transferred. Reserved values should not be used, see
.
31
30
29
28
27
26
25
24
DLYBCT
23
22
21
20
19
18
17
16
DLYBS
15
14
13
12
11
10
9
8
SCBR
7
6
5
4
3
2
1
0
BITS
CSAAT
CSNAAT
NCPHA
CPOL
32058K AVR32-01/12