3886 datasheet(208/380 Pages) RENESAS

208 / 380 page

3886 Group User’s Manual

APPLICATION

2-91

2.5 Multi-master I2C-BUS interface

➁ Transmission of command

Confirm correct completion of communication at ➀ before command transmission. When receiving

the STOP condition, a process not to transmit a command is required, because the internal I2C-

BUS generates an interrupt request also owing to the STOP condition transmitted to other devices.

After confirming correct completion of communication, write a command to the I2C data shift

In case the AL bit (bit 3 of address 001416) is “1”, check the slave address comparison flag (ASS

bit; bit 2 of address 001416) to judge whether the device given a right of master transmission owing

to an arbitration specifies itself as a slave address. When it is “1”, perform the slave reception;

when “0”, wait for a STOP condition occurrence caused by other devices and the communication

completion.

In case the AL bit is “0”, check the last received bit (LRB bit; bit 0 of address 001416). When it is

“1”, make the STOP condition generate and release the bus use, because the specified slave

device does not exist on the I2C-BUS.

Fig. 2.5.20 Transmission process of command

AL (address 1416), bit 3 ?

AAS (address 1416), bit 2 ?

0 (ACK)

0 (not detected)

Stop condition output

S0 (address 1216)

← 000011112

PIN (address 1416), bit 4 ?

1 (error)

0 (slave address transmitted)

LRB (address 1416), bit 0 ?

0(address not corresponded)

1 (NACK)

1 (detected)

1(address corresponded)

End

Re-transmission preparation

Slave reception

• Judgment of slave address comparison

• Judgment of bus hold

• Judgment of arbitration lost detection

• ACK confirmation

• Command data write to I2C data shift register

3886 Datasheet(PDF) 208 Page - Renesas Technology Corp