Section 17 I
2
C Bus Interface (IIC)
Rev. 3.00 Jan 25, 2006 page 517 of 872
REJ09B0286-0300
SDA
SCL
S
SLA
R/
W
A
9
8
1–7
9
8
1–7
9
8
1–7
DATA
A
DATA
A/
A
P
Figure 17.6 I
2
C Bus Timing
Legend:
S:
Start condition. The master device drives SDA from high to low while SCL is high.
SLA:
Slave address
R/
W
: Indicates the direction of data transfer: From the slave device to the master device when
R/
W
is 1, or from the master device to the slave device when R/
W
is 0.
A:
Acknowledge signal. The receiving device drives SDA to low.
DATA: Transmit/Receive data
P:
Stop condition. The master device drives SDA from low to high while SCL is high.
17.5.2
Master Transmit Operation
When data is set to ICDR during the period between the execution of an instruction to issue a start
condition and the creation of the start condition, the data may not be output normally, because
there will be a conflict between generation of a start condition and output of data. Although data
H'FF is to be sent to ICDR by a dummy write operation before an issue of a stop condition, the
H'FF data may be output by the dummy write operation if the execution of the instruction to issue
a stop condition is delayed. To prevent these problems, follow the flowchart shown below during
the master transmit operation.
In I
2
C bus format master transmit mode, the master device outputs the transmit clock and transmit
data, and the slave device returns an acknowledge signal. The transmission procedure and
operations for sequential data transmission in synchronization with the ICDR writing are described
below.
1. Set the ICE bit in ICCR to 1. Set bits MLS, WAIT, and CKS2 to CKS0 in ICMR, and bits
IICX1 and IICX0 in STCR, according to the operating mode.
2. Read the BBSY flag in ICCR to confirm that the bus is free.
3. Set bits MST and TRS to 1 in ICCR to select master transmit mode.
4. Write 1 to BBSY and 0 to SCP in ICCR. This changes SDA from high to low when SCL is
high, and generates the start condition.
Содержание H8S/2158
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Страница 36: ...Rev 3 00 Jan 25 2006 page xxxiv of lii B Product Lineup 863 C Package Dimensions 864 Index 865...
Страница 47: ...Rev 3 00 Jan 25 2006 page xlv of lii Appendix Figure C 1 Package Dimensions TBP 112A 864...
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Страница 70: ...Section 1 Overview Rev 3 00 Jan 25 2006 page 16 of 872 REJ09B0286 0300...
Страница 118: ...Section 3 MCU Operating Modes Rev 3 00 Jan 25 2006 page 64 of 872 REJ09B0286 0300...
Страница 126: ...Section 4 Exception Handling Rev 3 00 Jan 25 2006 page 72 of 872 REJ09B0286 0300...
Страница 198: ...Section 6 Bus Controller Rev 3 00 Jan 25 2006 page 144 of 872 REJ09B0286 0300...
Страница 326: ...Section 10 8 Bit PWM Timer PWM Rev 3 00 Jan 25 2006 page 272 of 872 REJ09B0286 0300...
Страница 440: ...Section 15 Watchdog Timer WDT Rev 3 00 Jan 25 2006 page 386 of 872 REJ09B0286 0300...
Страница 606: ...Section 17 I 2 C Bus Interface IIC Rev 3 00 Jan 25 2006 page 552 of 872 REJ09B0286 0300...
Страница 742: ...Section 19 Multimedia Card Interface MCIF Rev 3 00 Jan 25 2006 page 688 of 872 REJ09B0286 0300...
Страница 744: ...Section 20 Encryption Operation Circuit DES and GF Rev 3 00 Jan 25 2006 page 690 of 872 REJ09B0286 0300...
Страница 750: ...Section 21 D A Converter Rev 3 00 Jan 25 2006 page 696 of 872 REJ09B0286 0300...
Страница 768: ...Section 22 A D Converter Rev 3 00 Jan 25 2006 page 714 of 872 REJ09B0286 0300...
Страница 770: ...Section 23 RAM Rev 3 00 Jan 25 2006 page 716 of 872 REJ09B0286 0300...
Страница 824: ...Section 26 Clock Pulse Generator Rev 3 00 Jan 25 2006 page 770 of 872 REJ09B0286 0300...
Страница 844: ...Section 27 Power Down Modes Rev 3 00 Jan 25 2006 page 790 of 872 REJ09B0286 0300...
Страница 878: ...Section 28 List of Registers Rev 3 00 Jan 25 2006 page 824 of 872 REJ09B0286 0300...
Страница 926: ...Index Rev 3 00 Jan 25 2006 page 872 of 872 REJ09B0286 0300...