ATMEGA169 ATMEL [ATMEL Corporation], ATMEGA169 Datasheet - Page 151

• Manufacturer Part Number: ATMEGA169
• Description: 8-bit Microcontroller with 16K Bytes In-System Programmable Flash
• Manufacturer: ATMEL [ATMEL Corporation]

Data Modes
2514P–AVR–07/06
There are four combinations of SCK phase and polarity with respect to serial data,
which are determined by control bits CPHA and CPOL. The SPI data transfer formats
are shown in Figure 67 and Figure 68. Data bits are shifted out and latched in on oppo-
site edges of the SCK signal, ensuring sufficient time for data signals to stabilize. This is
clearly seen by summarizing Table 67 and Table 68, as done below:
Table 70. CPOL Functionality
Figure 67. SPI Transfer Format with CPHA = 0
Figure 68. SPI Transfer Format with CPHA = 1
CPOL=0, CPHA=0
CPOL=0, CPHA=1
CPOL=1, CPHA=0
CPOL=1, CPHA=1
SCK (CPOL = 0)
mode 0
SCK (CPOL = 1)
mode 2
SAMPLE I
MOSI/MISO
CHANGE 0
MOSI PIN
CHANGE 0
MISO PIN
SCK (CPOL = 0)
mode 1
SCK (CPOL = 1)
mode 3
SAMPLE I
MOSI/MISO
CHANGE 0
MOSI PIN
CHANGE 0
MISO PIN
SS
SS
MSB first (DORD = 0)
LSB first (DORD = 1)
MSB first (DORD = 0)
LSB first (DORD = 1)
MSB
LSB
MSB
LSB
Sample (Falling)
Sample (Rising)
Leading Edge
Bit 6
Bit 1
Setup (Falling)
Setup (Rising)
Bit 6
Bit 1
Bit 5
Bit 2
Bit 5
Bit 2
Bit 4
Bit 3
Bit 4
Bit 3
Bit 3
Bit 4
Sample (Falling)
Sample (Rising)
Setup (Falling)
Setup (Rising)
Trailing eDge
Bit 3
Bit 4
Bit 2
Bit 5
ATmega169/V
Bit 2
Bit 5
Bit 1
Bit 6
Bit 1
Bit 6
LSB
MSB
SPI Mode
LSB
MSB
0
1
2
3
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