13.5 Control in the I2C Bus Mode
13.5.1 Serial Clock
13.5.1.1 Clock source
SBICR1<SCK[2:0]> specifies the maximum frequency of the serial clock to be output from the SCL
pin in the master mode.
1/fscl
t
LOW
t
HIGH
t
LOW
= 2
n-1
/fsys + 58/fsys
t
HIGH
= 2
n-1
/fsys + 14/fsys
fscl = 1/(t
LOW
+ t
HIGH
)
=
2
n
+ 72
fsys
n
000
001
010
011
100
101
110
5
6
7
8
9
10
11
SBICR1<SCK[2:0]>
Figure 13-3 Clock source
Note:
The maximum speeds in the standard and high-speed modes are specified to 100kHz and
400kHz respectively following the communications standards. Notice that the internal SCL
clock frequency is determined by the fsys used and the calculation formula shown above.
13.5.1.2 Clock Synchronization
The I2C bus is driven by using the wired-AND connection due to its pin structure. The first master
that pulls its clock line to the "Low" level overrides other masters producing the "High" level on their
clock lines. This must be detected and responded by the masters producing the "High" level.
Clock synchronization assures correct data transfer on a bus that has two or more master.
For example, the clock synchronization procedure for a bus with two masters is shown below.
Wait for “High”level
period counting
Reset “High”level
period counting
Start “High” level period counting
a
b
c
Internal SCL output
(Master A)
Internal SCL output
(Master B)
SCL line
Figure 13-4 Example of Clock Synchronization
At the point a, Master A pulls its internal SCL output to the "Low" level, bringing the SCL bus line to
the "Low" level. Master B detects this transition, resets its "High" level period counter, and pulls its inter-
nal SCL output level to the "Low" level.
TMPM3V6/M3V4
13. Serial Bus Interface (I2C/SIO)
13.5 Control in the I2C Bus Mode
Page 280
2019-02-06
Содержание TMPM3V4
Страница 1: ...32 Bit RISC Microcontroller TX03 Series TMPM3V6 M3V4 ...
Страница 2: ... 2019 Toshiba Electronic Devices Storage Corporation ...
Страница 7: ...Revision History Date Revision Comment 2019 02 06 1 First Release ...
Страница 8: ......
Страница 22: ...xiv ...
Страница 52: ...TMPM3V6 M3V4 3 Processor Core 3 6 Exclusive access Page 30 2019 02 06 ...
Страница 148: ...TMPM3V6 M3V4 7 Exceptions 7 6 Exception Interrupt Related Registers Page 126 2019 02 06 ...
Страница 178: ...TMPM3V6 M3V4 9 Input Output port 9 2 Block Diagrams of Ports Page 156 2019 02 06 ...
Страница 206: ...TMPM3V6 M3V4 10 16 bit Timer Event Counters TMRB 10 7 Applications using the Capture Function Page 184 2019 02 06 ...
Страница 232: ...TMPM3V6 M3V4 11 Universal Asynchronous Receiver Transmitter Circuit UART 11 4 Operation Description Page 210 2019 02 06 ...
Страница 354: ...TMPM3V6 M3V4 14 Synchronous Serial Port SSP 14 6 Frame Format Page 332 2019 02 06 ...
Страница 419: ...TMPM3V6 M3V4 Page 397 2019 02 06 ...
Страница 420: ...TMPM3V6 M3V4 16 Analog Digital Converter ADC 16 6 Timing chart of AD conversion Page 398 2019 02 06 ...
Страница 462: ...TMPM3V6 M3V4 21 Watchdog Timer WDT 21 5 Control register Page 440 2019 02 06 ...
Страница 510: ...TMPM3V6 M3V4 22 Flash Memory Operation 22 4 Programming in the User Boot Mode Page 488 2019 02 06 ...
Страница 538: ...TMPM3V6 M3V4 25 Electrical Characteristics 25 7 Recommended Oscillation Circuit Page 516 2019 02 06 ...
Страница 541: ...26 3 TMPM3V4FWUG TMPM3V4FSUG Type LQFP64 P 1010 0 50E LPHQVLRQV TMPM3V6 M3V4 Page 519 2019 02 06 ...
Страница 544: ......