EFM8UB2 Datasheet, PDF (7/50 Pages) Silicon Laboratories – The EFM8UB2 highlighted features are listed below

3.6 Communications and Other Digital Peripherals
EFM8UB2 Data Sheet
System Overview
Universal Serial Bus (USB0)
The USB0 module provides Full/Low Speed function for USB peripheral implementations. The USB function controller (USB0) consists
of a Serial Interface Engine (SIE), USB transceiver (including matching resistors and configurable pull-up resistors), 1 KB FIFO block,
and clock recovery mechanism for crystal-less operation. No external components are required. The USB0 module is Universal Serial
Bus Specification 2.0 compliant.
The USB0 module includes the following features:
• Full and Low Speed functionality.
• Implements 4 bidirectional endpoints.
• USB 2.0 compliant USB peripheral support (no host capability).
• Direct module access to 1 KB of RAM for FIFO memory.
• Clock recovery to meet USB clocking requirements with no external components.
Universal Asynchronous Receiver/Transmitter (UART0)
UART0 is an asynchronous, full duplex serial port offering modes 1 and 3 of the standard 8051 UART. Enhanced baud rate support
allows a wide range of clock sources to generate standard baud rates. Received data buffering allows UART0 to start reception of a
second incoming data byte before software has finished reading the previous data byte.
The UART module provides the following features:
• Asynchronous transmissions and receptions
• Baud rates up to SYSCLK/2 (transmit) or SYSCLK/8 (receive)
• 8- or 9-bit data
• Automatic start and stop generation
Universal Asynchronous Receiver/Transmitter (UART1)
UART1 is an asynchronous, full duplex serial port offering a variety of data formatting options. A dedicated baud rate generator with a
16-bit timer and selectable prescaler is included, which can generate a wide range of baud rates. A received data FIFO allows UART1
to receive multiple bytes before data is lost and an overflow occurs.
UART1 provides the following features:
• Asynchronous transmissions and receptions.
• Dedicated baud rate generator supports baud rates up to SYSCLK/2 (transmit) or SYSCLK/8 (receive)
• 5, 6, 7, 8, or 9 bit data.
• Automatic start and stop generation.
• Automatic parity generation and checking.
• Three byte FIFO on receive.
Serial Peripheral Interface (SPI0)
The serial peripheral interface (SPI) module provides access to a flexible, full-duplex synchronous serial bus. The SPI can operate as a
master or slave device in both 3-wire or 4-wire modes, and supports multiple masters and slaves on a single SPI bus. The slave-select
(NSS) signal can be configured as an input to select the SPI in slave mode, or to disable master mode operation in a multi-master
environment, avoiding contention on the SPI bus when more than one master attempts simultaneous data transfers. NSS can also be
configured as a firmware-controlled chip-select output in master mode, or disabled to reduce the number of pins required. Additional
general purpose port I/O pins can be used to select multiple slave devices in master mode.
The SPI module includes the following features:
• Supports 3- or 4-wire operation in master or slave modes.
• Supports external clock frequencies up to SYSCLK / 2 in master mode and SYSCLK / 10 in slave mode.
• Support for four clock phase and polarity options.
• 8-bit dedicated clock clock rate generator.
• Support for multiple masters on the same data lines.
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