
I
2
C Interface
32-8
Freescale Semiconductor
Figure 32-7. I
2
C Standard Communication Protocol
32.3.2
Slave Address Transmission
The master sends the slave address in the first byte after the START signal (B). After the seven-bit calling
address, it sends the R/W bit (C), which tells the slave data transfer direction (0 equals write transfer, 1
equals read transfer).
Each slave must have a unique address. An I
2
C master must not transmit its own slave address; it cannot
be master and slave at the same time.
The slave whose address matches that sent by the master pulls I2C_SDA low at the ninth serial clock (D)
to return an acknowledge bit.
32.3.3
Data Transfer
When successful slave addressing is achieved, data transfer can proceed (see E in
byte-by-byte basis in the direction specified by the R/W bit sent by the calling master.
Data can be changed only while I2C_SCL is low and must be held stable while I2C_SCL is high, as
shows. I2C_SCL is pulsed once for each data bit, with the msb being sent first. The receiving
device must acknowledge each byte by pulling I2C_SDA low at the ninth clock; therefore, a data byte
transfer takes nine clock pulses. See
Figure 32-8. Data Transfer
1
2
3
4
5
6
7
8
1
2
3
4
5
6
7
8
9 9
AD7 AD6 AD5 AD4 AD3 AD2 AD1 R/W
XXX
D7
D6
D5
D4
D3
D2
D1
D0
Calling Address
R/W
ACK
Bit
Data Byte
No
ACK
Bit
STOP
Signal
lsb
msb
lsb
msb
START
Signal
A
B
D
C
E
F
Interrupt bit set
(Byte complete)
I2C_SCL
I2C_SDA
I2C_
SCL held low while
Interrupt is serviced
1
2
3
4
5
6
7
8
9
5
6
7
8
4
3
2
1
Bit6
Bit4
Bit3
Bit2
Bit1
Bit5
Bit7
Bit0
Bit6
Bit4
Bit3
Bit2
Bit1
Bit5
Bit0
Bit7
START
Signal
ACK from
Receiver
STOP
No
ACK Bit
Data Byte
Slave Address
R/W
Signal
Interrupt Bit Set
(Byte Complete)
9
I2C_SCL
I2C_SDA
I2C_
SCL held low while
Interrupt is serviced
MCF5329 Reference Manual, Rev 3
Содержание MCF5329
Страница 106: ...ColdFire Core 3 32 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 126: ...Enhanced Multiply Accumulate Unit EMAC 4 20 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 148: ...Cache 5 22 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 154: ...Static RAM SRAM 6 6 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 184: ...Power Management 8 18 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 204: ...Reset Controller Module 10 8 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 220: ...System Control Module SCM 11 16 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 228: ...Crossbar Switch XBS 12 8 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 268: ...General Purpose I O Module 13 40 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 392: ...SDRAM Controller SDRAMC 18 30 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 436: ...Fast Ethernet Controller FEC 19 44 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 564: ...Liquid Crystal Display Controller LCDC 22 44 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 594: ...FlexCAN 23 30 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 678: ...Pulse Width Modulation PWM Module 26 22 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 684: ...Watchdog Timer Module 27 6 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 692: ...Programmable Interrupt Timers PIT0 PIT3 28 8 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 704: ...DMA Timers DTIM0 DTIM3 29 12 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 720: ...Queued Serial Peripheral Interface QSPI 30 16 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 754: ...UART Modules 31 34 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 770: ...I2 C Interface 32 16 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 790: ...Message Digest Hardware Accelerator MDHA 33 20 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 866: ...Debug Module 36 50 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 902: ...Register Memory Map Quick Reference A 26 Freescale Semiconductor MCF5329 Reference Manual Rev 3...