SMBus provides a clock synchronization mechanism, similar to I
參數(shù)資料
型號: TOOLSTICK300DC
廠商: Silicon Laboratories Inc
文件頁數(shù): 18/178頁
文件大?。?/td> 0K
描述: TOOLSTICK DAUGHTER CARD
標準包裝: 1
系列: ToolStick
類型: MCU
適用于相關(guān)產(chǎn)品: C8051F300
所含物品: 子卡
C8051F300/1/2/3/4/5
114
Rev. 2.9
13.3.2. Clock Low Extension
SMBus provides a clock synchronization mechanism, similar to I2C, which allows devices with different
speed capabilities to coexist on the bus. A clock-low extension is used during a transfer in order to allow
slower slave devices to communicate with faster masters. The slave may temporarily hold the SCL line
LOW to extend the clock low period, effectively decreasing the serial clock frequency.
13.3.3. SCL Low Timeout
If the SCL line is held low by a slave device on the bus, no further communication is possible. Furthermore,
the master cannot force the SCL line high to correct the error condition. To solve this problem, the SMBus
protocol specifies that devices participating in a transfer must detect any clock cycle held low longer than
25 ms as a “timeout” condition. Devices that have detected the timeout condition must reset the communi-
cation no later than 10 ms after detecting the timeout condition.
When the SMBTOE bit in SMB0CF is set, Timer 2 is used to detect SCL low timeouts. Timer 2 is forced to
reload when SCL is high, and allowed to count when SCL is low. With Timer 2 enabled and configured to
overflow after 25 ms (and SMBTOE set), the Timer 2 interrupt service routine can be used to reset (disable
and reenable) the SMBus in the event of an SCL low timeout. Timer 2 configuration details can be found in
13.3.4. SCL High (SMBus Free) Timeout
The SMBus specification stipulates that if the SCL and SDA lines remain high for more that 50 s, the bus
is designated as free. When the SMBFTE bit in SMB0CF is set, the bus will be considered free if SCL and
SDA remain high for more than 10 SMBus clock source periods. If the SMBus is waiting to generate a
Master START, the START will be generated following this timeout. Note that a clock source is required for
free timeout detection, even in a slave-only implementation.
相關(guān)PDF資料
PDF描述
TOOLSTICK411DC TOOLSTICK DAUGHTER CARD
TOOLSTICK336DC DAUGHTER CARD TOOLSTICK C8051F33
SDR-2 SCOTCH CODE REFILL # 2
0210490198 CABLE JUMPER 1.25MM .127M 14POS
RSM08DRTH CONN EDGECARD 16POS DIP .156 SLD
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
TOOLSTICK300PP 功能描述:插座和適配器 Dev Tool for C8051F30X MCUs RoHS:否 制造商:Silicon Labs 產(chǎn)品:Adapter 用于:EM35x
TOOLSTICK300SPP 功能描述:插座和適配器 TS for F300-F305 SOIC 14 MCUs RoHS:否 制造商:Silicon Labs 產(chǎn)品:Adapter 用于:EM35x
TOOLSTICK310PP 功能描述:插座和適配器 C8051F310/12/14 F361 F364 F366 F368 RoHS:否 制造商:Silicon Labs 產(chǎn)品:Adapter 用于:EM35x
TOOLSTICK311DC 功能描述:子卡和OEM板 ToolStick C8051F311 Daughter Card RoHS:否 制造商:BeagleBoard by CircuitCo 產(chǎn)品:BeagleBone LCD4 Boards 用于:BeagleBone - BB-Bone - Open Source Development Kit
TOOLSTICK311PP 功能描述:插座和適配器 C8051F311/13/15 F362 F365 F367 F369 RoHS:否 制造商:Silicon Labs 產(chǎn)品:Adapter 用于:EM35x