I2C Interface Registers
MPC5200B Users Guide, Rev. 1
Freescale Semiconductor 18-5
Figure 18-6. Timing Diagram—Clock Synchronization
A data arbitration procedure determines the relative priority of contending masters. A bus master loses arbitration if it transmits logic “1”
while another master transmits logic “0”. Losing masters immediately switch to slave-receive mode and stop driving SDA output. In this case,
transition from master to slave mode does not generate a STOP condition. A status bit is hardware set to indicate loss of arbitration. See
Figure 18-7.
Figure 18-7. Timing Diagram—Arbitration Procedure
18.3 I2C Interface Registers
The I2C is controlled by 7 32-bit registers. The registers are located at an offset from MBAR of 0x3D00 (I2C1) and 0x3D40 (I2C2) . Register
addresses are relative to this offset. There is one I2C Interrupt Control Register only for both I2C modules. There is also one glitch filter control
register for both I2C modules.
Hyperlinks to the I2C Interface registers are provided below:
I2C Address Register (0x3D00) I2C Status Register (0x3D0C)
I2C Frequency Divider Register (0x3D04) I2C Data I /O Register (0x3D10)
I2C Control Register (0x3D08) I2C Interrupt Control Register (0x3D20)
I2C Filter Register (0x3D24)
Wait State
Start Counting
High Period
SCL by
SCL by
SCL
Master1
Master2
SCL
SDA by
Master1
SDA by
Master2
SDA
Master 2 Loses Arbitration,
and becomes slave-receiver