Section 18
I
2
C Bus Interface (IIC)
Rev. 1.00 Mar. 12, 2008 Page 589 of 1178
REJ09B0403-0100
18.3 Register
Descriptions
The I
2
C bus interface has the following registers. Registers ICDR and SARX and registers ICMR
and SAR are allocated to the same addresses. Accessible registers differ depending on the ICE bit
in ICCR. When the ICE bit is cleared to 0, SAR and SARX can be accessed, and when the ICE bit
is set to 1, ICMR and ICDR can be accessed.
•
I
2
C bus data register (ICDR)
•
Slave address register (SAR)
•
Second slave address register (SARX)
•
I
2
C bus mode register (ICMR)
•
I
2
C bus transfer rate select register (IICX3)
•
I
2
C bus control register (ICCR)
•
I
2
C bus status register (ICSR)
•
I
2
C bus extended control register (ICXR)
•
I
2
C SMbus control register (ICSMBCR)
18.3.1 I
2
C Bus Data Register (ICDR)
ICDR is an 8-bit readable/writable register that is used as a transmit data register when
transmitting and a receive data register when receiving. ICDR is divided internally into a shift
register (ICDRS), receive buffer (ICDRR), and transmit buffer (ICDRT). Data transfers among the
three registers are performed automatically in accordance with changes in the bus state, and they
affect the status of internal flags such as ICDRE and ICDRF.
In master transmit mode with the I
2
C bus format, writing transmit data to ICDR should be
performed after start condition detection. When the start condition is detected, previous write data
is ignored. In slave transmit mode, writing should be performed after the slave addresses match
and the TRS bit is automatically changed to 1.
If IIC is in transmit mode (TRS=1) and the next data is in ICDRT (the ICDRE flag is 0), data is
transferred automatically from ICDRT to ICDRS, following transmission of one frame of data
using ICDRS. When the ICDRE flag is 1 and the next transmit data writing is waited, data is
transferred automatically from ICDRT to ICDRS by writing to ICDR. If IIC is in receive mode
(TRS=0), no data is transferred from ICDRT to ICDRS. Note that data should not be written to
ICDR in receive mode.
Reading receive data from ICDR is performed after data is transferred from ICDRS to ICDRR.
Summary of Contents for H8S Family
Page 2: ...Rev 1 00 Mar 12 2008 Page ii of xIviii...
Page 8: ...Rev 1 00 Mar 12 2008 Page viii of xIviii...
Page 28: ...Rev 1 00 Mar 12 2008 Page xxviii of xIviii...
Page 48: ...Rev 1 00 Mar 12 2008 Page xlviii of xIviii...
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...
Page 1226: ...Rev 1 00 Mar 12 2008 Page 1178 of 1178 REJ09B0403 0100...
Page 1229: ......
Page 1230: ...H8S 2472 Group H8S 2462 Group Hardware Manual...