C8051T610DK Silicon Laboratories Inc, C8051T610DK Datasheet - Page 114

• Manufacturer Part Number: C8051T610DK
• Description: KIT DEV FOR C8051T61X MCU'S
• Manufacturer: Silicon Laboratories Inc
• Type: MCUr

Specifications of C8051T610DK

• Contents: Board, daughter boards, power adapter, cables, documentation and software
• Processor To Be Evaluated: C8051T61x
• Interface Type: USB
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: C8051T610
• For Use With: 336-1507 - DAUGHTER BOARD T610 24QFN SOCKET336-1506 - DAUGHTER BOARD T610 28QFN SOCKET336-1505 - DAUGHT BOARD T610 32TQFP SOCKET
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 336-1443

C8051T610/1/2/3/4/5/6/7
21.1. Port I/O Modes of Operation
Port pins use the Port I/O cell shown in Figure 21.2. Each Port I/O cell can be configured by software for
analog I/O or digital I/O using the PnMDIN registers. On reset, all Port I/O cells default to a high impedance
state with weak pull-ups enabled until the Crossbar is enabled (XBARE = 1).
21.1.1. Port Pins Configured for Analog I/O
Any pins to be used as Comparator or ADC input, external oscillator input/output, or VREF should be con-
figured for analog I/O (PnMDIN.n = 1). When a pin is configured for analog I/O, its weak pullup, digital
driver, and digital receiver are disabled. Port pins configured for analog I/O will always read back a value of
0.
Configuring pins as analog I/O saves power and isolates the Port pin from digital interference. Port pins
configured as digital inputs may still be used by analog peripherals; however, this practice is not recom-
mended and may result in measurement errors.
21.1.2. Port Pins Configured For Digital I/O
Any pins to be used by digital peripherals (UART, SPI, SMBus, etc.), external digital event capture func-
tions, or as GPIO should be configured as digital I/O (PnMDIN.n = 1). For digital I/O pins, one of two output
modes (push-pull or open-drain) must be selected using the PnMDOUT registers.
Push-pull outputs (PnMDOUT.n = 1) drive the Port pad to the VDD or GND supply rails based on the out-
put logic value of the Port pin. Open-drain outputs have the high side driver disabled; therefore, they only
drive the Port pad to GND when the output logic value is 0 and become high impedance inputs (both high
low drivers turned off) when the output logic value is 1.
When a digital I/O cell is placed in the high impedance state, a weak pull-up transistor pulls the Port pad to
the VDD supply voltage to ensure the digital input is at a defined logic state. Weak pull-ups are disabled
when the I/O cell is driven to GND to minimize power consumption and may be globally disabled by setting
WEAKPUD to 1. The user should ensure that digital I/O are always internally or externally pulled or driven
to a valid logic state to minimize power consumption. Port pins configured for digital I/O always read back
the logic state of the Port pad, regardless of the output logic value of the Port pin.
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