Section 18
I
2
C Bus Interface (IIC)
Rev. 1.00 Mar. 12, 2008 Page 651 of 1178
REJ09B0403-0100
18.6 Usage
Notes
1. In master mode, if an instruction to generate a start condition is immediately followed by an
instruction to generate a stop condition, neither condition will be output correctly. To output
consecutive start and stop conditions*, after issuing the instruction that generates the start
condition, read the relevant DR registers of I
2
C bus output pins, check that SCL and SDA are
both low. If the ICE bit is set to 1, pin state can be monitored by reading DR register. Then
issue the instruction that generates the stop condition. Note that SCL may not yet have gone
low when BBSY is cleared to 0.
Note: * An illegal procedure in the I
2
C bus specification.
2. Either of the following two conditions will start the next transfer. Pay attention to these
conditions when accessing to ICDR.
Write to ICDR when ICE = 1 and TRS = 1 (including automatic transfer from ICDRT to
ICDRS)
Read from ICDR when ICE = 1 and TRS = 0 (including automatic transfer from ICDRS to
ICDRR)
3. Table 18.11 shows the timing of SCL and SDA outputs in synchronization with the internal
clock. Timings on the bus are determined by the rise and fall times of signals affected by the
bus load capacitance, series resistance, and parallel resistance.
Table 18.11 I
2
C Bus Timing (SCL and SDA Outputs)
Item Symbol
Output
Timing
Unit
Notes
SCL output cycle time
t
SCLO
28
t
cyc
to 512 t
cyc
ns
SCL output high pulse width
t
SCLHO
0.5
t
SCLO
ns
SCL output low pulse width
t
SCLLO
0.5
t
SCLO
ns
SDA output bus free time
t
BUFO
0.5
t
SCLO
– 1 t
cyc
ns
Start condition output hold time
t
STAHO
0.5
t
SCLO
– 1 t
cyc
ns
Retransmission start condition output
setup time
t
STASO
1
t
SCLO
ns
Stop condition output setup time
t
STOSO
0.5
t
SCLO
+ 2 t
cyc
ns
Data output setup time (master)
1 t
SCLLO
– 3 t
cyc
Data output setup time (slave)
t
SDASO
1 t
SCLLO
– (6 t
cyc
or 12 t
cyc
*
)
ns
Data output hold time
t
SDAHO
3
t
cyc
ns
See figure
31.32
(reference)
Note:
*
6
t
cyc
when IICXn is 0, 12 t
cyc
when IICXn is 1 (n = 0 to 5).
Содержание H8S Family
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Страница 152: ...Section 5 Interrupt Controller Rev 1 00 Mar 12 2008 Page 104 of 1178 REJ09B0403 0100...
Страница 206: ...Section 6 Bus Controller BSC Rev 1 00 Mar 12 2008 Page 158 of 1178 REJ09B0403 0100...
Страница 420: ...Section 9 14 Bit PWM Timer PWMX Rev 1 00 Mar 12 2008 Page 372 of 1178 REJ09B0403 0100...
Страница 476: ...Section 12 Watchdog Timer WDT Rev 1 00 Mar 12 2008 Page 428 of 1178 REJ09B0403 0100...
Страница 552: ...Section 14 CRC Operation Circuit CRC Rev 1 00 Mar 12 2008 Page 504 of 1178 REJ09B0403 0100...
Страница 588: ...Section 15 Serial Communication Interface with FIFO SCIF Rev 1 00 Mar 12 2008 Page 540 of 1178 REJ09B0403 0100...
Страница 632: ...Section 17 Synchronous Serial Communication Unit SSU Rev 1 00 Mar 12 2008 Page 584 of 1178 REJ09B0403 0100...
Страница 712: ...Section 18 I2 C Bus Interface IIC Rev 1 00 Mar 12 2008 Page 664 of 1178 REJ09B0403 0100...
Страница 804: ...Section 19 LPC Interface LPC Rev 1 00 Mar 12 2008 Page 756 of 1178 REJ09B0403 0100...
Страница 838: ...Section 20 Ethernet Controller EtherC Rev 1 00 Mar 12 2008 Page 790 of 1178 REJ09B0403 0100...
Страница 964: ...Section 24 RAM Rev 1 00 Mar 12 2008 Page 916 of 1178 REJ09B0403 0100...
Страница 1066: ...Section 25 Flash Memory Rev 1 00 Mar 12 2008 Page 1018 of 1178 REJ09B0403 0100...
Страница 1098: ...Section 26 Boundary Scan JTAG Rev 1 00 Mar 12 2008 Page 1050 of 1178 REJ09B0403 0100...
Страница 1168: ...Section 30 Platform Environment Control Interface PECI Rev 1 00 Mar 12 2008 Page 1120 of 1178 REJ09B0403 0100...
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Страница 1230: ...H8S 2472 Group H8S 2462 Group Hardware Manual...