Section 17 I
2
C Bus Interface (IIC)
Rev. 3.00 Jan 25, 2006 page 548 of 872
REJ09B0286-0300
To receive the address in slave mode, clear the TRS bit to 0 during the time indicated as (a) in
figure 17.27.
To release the SCL low level that is held by means of the wait function in slave mode, clear the
TRS bit to and then dummy-read ICDR.
Restart condition
Data
transmission
Address reception
SCL
TRS
TRS bit setting is suspended in this period
ICDR dummy read
TRS bit setting
(a)
(b)
8
A
9
1
2
3
4
5
6
7
8
9
The rise of the 9th clock is detected
SDA
The rise of the 9th clock is detected
Figure 17.27 TRS Bit Set Timing in Slave Mode
13. Note on ICDR read in transmit mode and ICDR write in receive mode
When ICDR is read in transmit mode (TRS = 1) or ICDR is written to in receive mode (TRS =
0), the SCL pin may not be held low in some cases after transmit/receive operation has been
completed, thus inconveniently allowing clock pulses to be output on the SCL bus line before
ICDR is accessed correctly.
To access ICDR correctly, read the ICDR after setting receive mode or write to the ICDR after
setting transmit mode.
14. Note on ACKE and TRS bits in slave mode
In the I
2
C bus interface, if 1 is received as the acknowledge bit value (ACKB = 1) in transmit
mode (TRS = 1) and then the address is received in slave mode without performing appropriate
processing, interrupt handling may start at the rising edge of the 9th clock pulse even when the
address does not match.
Similarly, if the start condition or address is transmitted from the master device in slave
transmit mode (TRS = 1) and 1 is received as the acknowledge bit value (ACKB = 1), the IRIC
flag may be set thus causing an interrupt source even when the address does not match.
To use the I
2
C bus interface module in slave mode, be sure to follow the procedures below.
Содержание H8S/2158
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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...
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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...