C8051F044-GQR Silicon Laboratories Inc, C8051F044-GQR Datasheet - Page 246

• Manufacturer Part Number: C8051F044-GQR
• Description: IC 8051 MCU 64K FLASH 100TQFP
• Manufacturer: Silicon Laboratories Inc
• Series: C8051F04xr

Specifications of C8051F044-GQR

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 25MHz
• Connectivity: CAN, EBI/EMI, SMBus (2-Wire/I²C), SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, Temp Sensor, WDT
• Number Of I /o: 64
• Program Memory Size: 64KB (64K x 8)
• Program Memory Type: FLASH
• Ram Size: 4.25K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 3.6 V
• Data Converters: A/D 13x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 100-TQFP, 100-VQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -

C8051F040/1/2/3/4/5/6/7
Setting the SMBus0 Free Timer Enable bit (FTE, SMB0CN.1) to logic 1 enables the timer in SMB0CR.
When SCL goes high, the timer in SMB0CR counts up. A timer overflow indicates a free bus timeout: if
SMBus0 is waiting to generate a START, it will do so after this timeout. The bus free period should be less
than 50 µs (see SFR Definition 19.2, SMBus0 Clock Rate Register).
When the TOE bit in SMB0CN is set to logic 1, Timer 4 is used to detect SCL low timeouts. If Timer 4 is
enabled (see
Section “23.2. Timer 2, Timer 3, and Timer 4” on page
295), Timer 4 is forced to reload
when SCL is high, and forced to count when SCL is low. With Timer 4 enabled and configured to overflow
after 25 ms (and TOE set), a Timer 4 overflow indicates a SCL low timeout; the Timer 4 interrupt service
routine can then be used to reset SMBus0 communication in the event of an SCL low timeout.
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