MC68HC908AP16CFA MOTOROLA [Motorola, Inc], MC68HC908AP16CFA Datasheet - Page 343

• Manufacturer Part Number: MC68HC908AP16CFA
• Description: Microcontrollers
• Manufacturer: MOTOROLA [Motorola, Inc]

16.9 SMBus Protocol Implementation
MC68HC908AP Family — Rev. 2.5
MOTOROLA
MASTER MODE
START
SLAVE MODE
START
OPERATION:
Prepare for Master mode
ACTION:
1. Load slave address to MMADR
2. Clear MMRW
3. Load command to MMDTR
4. Set MMAST
OPERATION:
Prepare for Slave mode
ACTION:
1. Load slave address to MMADR
2. Clear MMTXAK
3. Clear MMAST
Shaded data packets indicate transmissions by the MCU
Address
Address
OPERATION:
Slave address match and
FLAGS:
MMRXIF set
MMATCH set
MMSRW depends on 8th
ACTION:
1. Check MMSRW
2. Read Slave address
check for data direction
bit of calling address byte
OPERATION:
Prepare for repeated START
FLAGS:
MMTXIF set
MMRXAK clear
ACTION:
1. Set MMRW
2. Set REPSEN
3. Clear MMTXAK
4. Load dummy ($FF) to MMDTR
0
0
ACK
ACK
Command
Command
Figure 16-20. SMBus Protocol Implementation
OPERATION:
Read and decode received command
FLAGS:
MMRXIF set
MMATCH clear
ACTION:
Load Data1 to MMDTR
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ACK
ACK
OPERATION:
Slave address match and
FLAGS:
MMRXIF set
MMATCH set
MMSRW depends on 8th
ACTION:
Check MMSRW
get ready to transmit data
bit of calling address byte
START
START
OPERATION:
Get ready to receive data
FLAGS:
MMTXIF set
MMRXAK clear
ACTION:
Load dummy ($FF) to MMDTR
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Address
Address
1
1
ACK
ACK
OPERATION:
Transmit data
FLAGS:
MMTXIF set
ACTION:
Load Data2 to MMDTR
RX Data1
TX Data1
OPERATION:
Read received data
FLAGS:
MMRXIF set
ACTION:
Read Data1 from MMDRR
OPERATION:
Transmit data
FLAGS:
MMTXIF set
MMRXAK clear
ACTION:
Load Data3 to MMDTR
OPERATION:
Read received data and prepare for STOP
FLAGS:
MMRXIF set
ACTION:
1. Set MMTXAK
2. Read Data(N-1) from MMDRR
3. Clear MMAST
ACK
ACK
Multi-Master IIC Interface (MMIIC)
OPERATION:
Last data is going to be sent
FLAGS:
MMTXIF set
MMRXAK clear
ACTION:
Load dummy ($FF) to MMDTR
SMBus Protocol Implementation
ACK
ACK
OPERATION:
Last data sent
FLAGS:
MMTXIF set
MMRXAK set
ACTION:
Load dummy ($FF) to MMDTR
RX DataN
TX DataN
OPERATION:
Generate STOP
FLAGS:
MMRXIF set
ACTION:
Read DataN from MMDRR
NAK
NAK
Data Sheet
STOP
STOP
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