C8051F040-GQR Silicon Laboratories Inc, C8051F040-GQR Datasheet - Page 207

• Manufacturer Part Number: C8051F040-GQR
• Description: IC 8051 MCU 64K FLASH 100TQFP
• Manufacturer: Silicon Laboratories Inc
• Series: C8051F04xr

Specifications of C8051F040-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 8x8b, 13x12b; D/A 2x10b, 2x12b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 100-TQFP, 100-VQFP
• For Use With: 336-1205 - DEV KIT FOR F040/F041/F042/F043
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -

a digital input by setting P3MDOUT.7 to a logic 0, which selects open-drain output mode, and P3.7 to a
logic 1, which disables the low-side output driver.
If the Port pin has been assigned to a digital peripheral by the Crossbar and that pin functions as an input
(for example RX0, the UART0 receive pin), then the output drivers on that pin are automatically disabled.
17.1.4. Weak Pullups
By default, each Port pin has an internal weak pullup device enabled which provides a resistive connection
(about 100 k) between the pin and V
logic 1 to the Weak Pullup Disable bit, (WEAKPUD, XBR2.7). The weak pullup is automatically deactivated
on any pin that is driving a logic 0; that is, an output pin will not contend with its own pullup device. The
weak pullup device can also be explicitly disabled on Ports 1, 2, and 3 pin by configuring the pin as an
Analog Input, as described below.
17.1.5. Configuring Port 1, 2, and 3 Pins as Analog Inputs
The pins on Port 1 can serve as analog inputs to the ADC2 analog MUX (C8051F040/1/2/3 only), the pins
on Port 2 can serve as analog inputs to the Comparators, and the pins on Port 3 can serve as inputs to
ADC0. A Port pin is configured as an Analog Input by writing a logic 0 to the associated bit in the PnMDIN
registers. All Port pins default to a Digital Input mode. Configuring a Port pin as an analog input:

Note that the output drivers on a pin configured as an Analog Input are not explicitly disabled. Therefore,
the associated PnMDOUT bits of pins configured as Analog Inputs should explicitly be set to logic 0
(Open-Drain output mode), and the associated Port Data bits should be set to logic 1 (high-impedance).
Also note that it is not required to configure a Port pin as an Analog Input in order to use it as an input to
the ADC’s or Comparators; however, it is strongly recommended. See the analog peripheral’s correspond-
ing section in this datasheet for further information.
1. Disables the digital input path from the pin. This prevents additional power supply current from
2. Disables the weak pullup device on the pin.
3. Causes the Crossbar to “skip over” the pin when allocating Port pins for digital peripherals.
being drawn when the voltage at the pin is near V
a logic 0 regardless of the voltage at the Port pin.
DD
. The weak pullup devices can be globally disabled by writing a
Rev. 1.5
C8051F040/1/2/3/4/5/6/7
DD
/ 2. A read of the Port Data bit will return
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