C8051F350 Silicon Laboratories Inc, C8051F350 Datasheet - Page 152

• Manufacturer Part Number: C8051F350
• Description: IC 8051 MCU 8K FLASH 32LQFP
• Manufacturer: Silicon Laboratories Inc
• Series: C8051F35xr

Specifications of C8051F350

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 50MHz
• Connectivity: SMBus (2-Wire/I²C), SPI, UART/USART
• Peripherals: POR, PWM, Temp Sensor, WDT
• Number Of I /o: 17
• Program Memory Size: 8KB (8K x 8)
• Program Memory Type: FLASH
• Ram Size: 768 x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 3.6 V
• Data Converters: A/D 8x24b; D/A 2x8b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 32-LQFP
• Data Bus Width: 8 bit
• Data Rom Size: 128 B
• On-chip Adc: 10 bit
• Number Of Timers: 16 bit
• Operating Supply Voltage: 2.7 V to 3.6 V
• Mounting Style: SMD/SMT
• Height: 1.4 mm
• Length: 7 mm
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Width: 7 mm
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -
• Lead Free Status / Rohs Status: No RoHS Version Available

C8051F350/1/2/3
19.4.1. SMBus Configuration Register
The SMBus Configuration register (SMB0CF) is used to enable the SMBus Master and/or Slave modes,
select the SMBus clock source, and select the SMBus timing and timeout options. When the ENSMB bit is
set, the SMBus is enabled for all master and slave events. Slave events may be disabled by setting the
INH bit. With slave events inhibited, the SMBus interface will still monitor the SCL and SDA pins; however,
the interface will NACK all received addresses and will not generate any slave interrupts. When the INH bit
is set, all slave events will be inhibited following the next START (interrupts will continue for the duration of
the current transfer).
The SMBCS1-0 bits select the SMBus clock source, which is used only when operating as a master or
when the Free Timeout detection is enabled. When operating as a master, overflows from the selected
source determine the absolute minimum SCL low and high times as defined in Equation 19.1. Note that the
selected clock source may be shared by other peripherals so long as the timer is left running at all times.
For example, Timer 1 overflows may generate the SMBus and UART baud rates simultaneously. Timer
configuration is covered in
The selected clock source should be configured to establish the minimum SCL High and Low times as per
Equation 19.1. When the interface is operating as a master (and SCL is not driven or extended by any
other devices on the bus), the typical SMBus bit rate is approximated by Equation 19.2.
152
Equation 19.1. Minimum SCL High and Low Times
SMBCS1
Table 19.1. SMBus Clock Source Selection
Section “22. Timers” on page
T
Equation 19.2. Typical SMBus Bit Rate
HighMin
0
0
1
1
BitRate
SMBCS0
=
T
0
1
0
1
LowMin
=
f
--------------------------------------------- -
ClockSourceOverflow
SMBus Clock Source
Rev. 0.4
Timer 2 High Byte Overflow
=
Timer 2 Low Byte Overflow
--------------------------------------------- -
f
ClockSourceOverflow
Timer 0 Overflow
Timer 1 Overflow
191.
3
1