Section 18
I
2
C Bus Interface (IIC)
Rev. 1.00 Mar. 12, 2008 Page 663 of 1178
REJ09B0403-0100
S
S
S
A
A
A
A
A
SLA
SLA
SLA
DATA1
DATA2
SLA
R/
W
R/
W
R/
W
R/
W
A
DATA3
A
DATA4
I2C bus interface
(Master transmit mode)
Transmit data match
Transmit timing match
•
Receive address is ignored
•
Automatically transferred to slave
receive mode
•
Receive data is recognized as an
address
•
When the receive data matches to
the address set in the SAR or SARX
register, the I2C bus interface operates
as a slave device.
•
Arbitration is lost
•
The AL flag in ICSR is set to 1
Transmit data does not match
Data contention
Other device
(Master transmit mode)
I2C bus interface
(Slave receive mode)
Figure 18.35 Diagram of Erroneous Operation when Arbitration Lost
Though it is prohibited in the normal I
2
C protocol, the same problem may occur when the MST
bit is erroneously set to 1 and a transition to master mode is occurred during data transmission
or reception in slave mode.
When the MST bit is set to 1 during data transmission or reception in slave mode, the
arbitration decision circuit is enabled and arbitration is lost if conditions are satisfied. In this
case, the transmit/receive data which is not an address may be erroneously recognized as an
address.
In multi-master mode, pay attention to the setting of the MST bit when a bus conflict may
occur. In this case, the MST bit in the ICCR register should be set to 1 according to the order
below.
A. Make sure that the BBSY flag in the ICCR register is 0 and the bus is free before setting
the MST bit.
B. Set the MST bit to 1.
C. To confirm that the bus was not entered to the busy state while the MST bit is being set,
check that the BBSY flag in the ICCR register is 0 immediately after the MST bit has been
set.
Note: Above restrictions can be released by setting the bits FNC1 and FNC2 in ICXR to B'11.
Summary of Contents for H8S Family
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Page 70: ...Section 1 Overview Rev 1 00 Mar 12 2008 Page 22 of 1178 REJ09B0403 0100...
Page 108: ...Section 2 CPU Rev 1 00 Mar 12 2008 Page 60 of 1178 REJ09B0403 0100...
Page 116: ...Section 3 MCU Operating Modes Rev 1 00 Mar 12 2008 Page 68 of 1178 REJ09B0403 0100...
Page 152: ...Section 5 Interrupt Controller Rev 1 00 Mar 12 2008 Page 104 of 1178 REJ09B0403 0100...
Page 206: ...Section 6 Bus Controller BSC Rev 1 00 Mar 12 2008 Page 158 of 1178 REJ09B0403 0100...
Page 420: ...Section 9 14 Bit PWM Timer PWMX Rev 1 00 Mar 12 2008 Page 372 of 1178 REJ09B0403 0100...
Page 476: ...Section 12 Watchdog Timer WDT Rev 1 00 Mar 12 2008 Page 428 of 1178 REJ09B0403 0100...
Page 552: ...Section 14 CRC Operation Circuit CRC Rev 1 00 Mar 12 2008 Page 504 of 1178 REJ09B0403 0100...
Page 712: ...Section 18 I2 C Bus Interface IIC Rev 1 00 Mar 12 2008 Page 664 of 1178 REJ09B0403 0100...
Page 804: ...Section 19 LPC Interface LPC Rev 1 00 Mar 12 2008 Page 756 of 1178 REJ09B0403 0100...
Page 838: ...Section 20 Ethernet Controller EtherC Rev 1 00 Mar 12 2008 Page 790 of 1178 REJ09B0403 0100...
Page 964: ...Section 24 RAM Rev 1 00 Mar 12 2008 Page 916 of 1178 REJ09B0403 0100...
Page 1066: ...Section 25 Flash Memory Rev 1 00 Mar 12 2008 Page 1018 of 1178 REJ09B0403 0100...
Page 1098: ...Section 26 Boundary Scan JTAG Rev 1 00 Mar 12 2008 Page 1050 of 1178 REJ09B0403 0100...
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Page 1230: ...H8S 2472 Group H8S 2462 Group Hardware Manual...