C8051F314R Silicon Labs, C8051F314R Datasheet - Page 148

no-image

C8051F314R

Manufacturer Part Number
C8051F314R
Description
8-bit Microcontrollers - MCU 8KB 10ADC
Manufacturer
Silicon Labs
Datasheet

Specifications of C8051F314R

Product Category
8-bit Microcontrollers - MCU
Core
8051
Data Bus Width
8 bit
Maximum Clock Frequency
25 MHz
Program Memory Size
8 KB
Data Ram Size
1.25 KB
On-chip Adc
Yes
Operating Supply Voltage
2.7 V to 3.6 V
Package / Case
LQFP-32
Mounting Style
SMD/SMT
A/d Bit Size
10 bit
A/d Channels Available
17
Data Rom Size
128 B
Interface Type
I2C, SMBus, SPI, UART
Maximum Operating Temperature
+ 85 C
Minimum Operating Temperature
- 40 C
Number Of Programmable I/os
29
Number Of Timers
5
On-chip Dac
No
Processor Series
C8051
Program Memory Type
Flash
Factory Pack Quantity
500
Supply Voltage - Max
3.6 V
Supply Voltage - Min
2.7 V
C8051F310/1/2/3/4/5/6/7
14.3.2. 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.
14.3.3. 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 3 is used to detect SCL low timeouts. Timer 3 is forced to
reload when SCL is high, and allowed to count when SCL is low. With Timer 3 enabled and configured to
overflow after 25 ms (and SMBTOE set), the Timer 3 interrupt service routine can be used to reset (disable
and re-enable) the SMBus in the event of an SCL low timeout.
14.3.4. SCL High (SMBus Free) Timeout
The SMBus specification stipulates that if the SCL and SDA lines remain high for more that 50 µs, 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.
148
Rev. 1.7

Related parts for C8051F314R