C8051F131R Silicon Labs, C8051F131R Datasheet - Page 267

• Manufacturer Part Number: C8051F131R
• Description: 8-bit Microcontrollers - MCU 128kB 100MIPS 8448B RAM
• Manufacturer: Silicon Labs

Specifications of C8051F131R

• Product Category: 8-bit Microcontrollers - MCU
• Core: 8051
• Data Bus Width: 8 bit
• Maximum Clock Frequency: 100 MHz
• Program Memory Size: 128 KB
• Data Ram Size: 8.25 KB
• On-chip Adc: Yes
• Operating Supply Voltage: 2.7 V to 3.6 V
• Package / Case: TQFP-64
• Mounting Style: SMD/SMT
• A/d Bit Size: 10 bit
• A/d Channels Available: 9
• Data Rom Size: 64 KB
• Interface Type: I2C, SMBus, SPI, UART
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Number Of Programmable I/os: 32
• Number Of Timers: 16 bit
• Processor Series: C8051
• Program Memory Type: Flash
• Factory Pack Quantity: 500
• Supply Voltage - Max: 3.6 V
• Supply Voltage - Min: 3 V

19.4.2. Clock Rate Register
Bits7–0: SMB0CR.[7:0]: SMBus0 Clock Rate Preset
R/W
Bit7
The SMB0CR Clock Rate register controls the frequency of the serial clock SCL in master
mode. The 8-bit word stored in the SMB0CR Register preloads a dedicated 8-bit timer. The
timer counts up, and when it rolls over to 0x00, the SCL logic state toggles.
The SMB0CR setting should be bounded by the following equation , where SMB0CR is the
unsigned 8-bit value in register SMB0CR, and SYSCLK is the system clock frequency in
MHz:
The resulting SCL signal high and low times are given by the following equations, where
SYSCLK is the system clock frequency in Hz:
Using the same value of SMB0CR from above, the Bus Free Timeout period is given in the
following equation:
R/W
Bit6
SFR Definition 19.2. SMB0CR: SMBus0 Clock Rate
SMB0CR
T
HIGH
R/W
Bit5
T
LOW
T

BFT
4


=




288 0.85
10
R/W
Bit4
4
258 SMB0CR


–

–
256 SMB0CR
4
------------------------------------------------------------- -

Rev. 1.4

–
256 SMB0CR
R/W
Bit3

SYSCLK
--------------------- -
SYSCLK
–
C8051F120/1/2/3/4/5/6/7
4


SYSCLK
R/W
Bit2
 1.125




SYSCLK

+
C8051F130/1/2/3
+
1
625ns
R/W
Bit1
SFR Address:
SFR Page:
R/W
Bit0
0xCF
0
00000000
Reset Value
267