at91sam9g20-cu ATMEL Corporation, at91sam9g20-cu Datasheet - Page 403

• Manufacturer Part Number: at91sam9g20-cu
• Description: At91 Arm Thumb Microcontrollers
• Manufacturer: ATMEL Corporation

30.7.2
Name:
Access Type:
• MSTR: Master/Slave Mode
0 = SPI is in Slave mode.
1 = SPI is in Master mode.
• PS: Peripheral Select
0 = Fixed Peripheral Select.
1 = Variable Peripheral Select.
• PCSDEC: Chip Select Decode
0 = The chip selects are directly connected to a peripheral device.
1 = The four chip select lines are connected to a 4- to 16-bit decoder.
When PCSDEC equals one, up to 15 Chip Select signals can be generated with the four lines using an external 4- to 16-bit
decoder. The Chip Select Registers define the characteristics of the 15 chip selects according to the following rules:
• MODFDIS: Mode Fault Detection
0 = Mode fault detection is enabled.
1 = Mode fault detection is disabled.
• LLB: Local Loopback Enable
0 = Local loopback path disabled.
1 = Local loopback path enabled.
LLB controls the local loopback on the data serializer for testing in Master Mode only. (MISO is internally connected on
MOSI.)
• PCS: Peripheral Chip Select
This field is only used if Fixed Peripheral Select is active (PS = 0).
6384B–ATARM–15-Dec-08
LLB
SPI_CSR0 defines peripheral chip select signals 0 to 3.
SPI_CSR1 defines peripheral chip select signals 4 to 7.
SPI_CSR2 defines peripheral chip select signals 8 to 11.
SPI_CSR3 defines peripheral chip select signals 12 to 14.
31
23
15
–
–
7
SPI Mode Register
30
22
14
SPI_MR
Read/Write
–
–
6
–
29
21
13
–
–
5
–
MODFDIS
28
20
12
–
–
4
DLYBCS
27
19
11
–
3
AT91SAM9G20 Preliminary
PCSDEC
26
18
10
–
2
PCS
PS
25
17
–
9
1
MSTR
24
16
–
8
0
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