原标题：ST STM32F103T80 USB、UART转换器参考设计方案

　　ST公司的STM32F103T8是一款STM32F103xx系列中密度性能的产品线，包含高性能ARM Cortex-M3 32位内核，最高主频为72MHz，内嵌高速存储器(Flash为128K，SRAM为20K)，提供2个12位ADC，3个16位定时器和一个PWM定时器。接口主要有2个IIC、2个SPI、3个UART，1个USB和1个CAN总线。本文首先介绍芯片的简介、特性、内部框图及应用领域，并给出相应设计方案的设计原理图、元器件列表及制板图。

　　The STM32F103xx medium-density performance line family incorporates the highperformance ARM Cortex™-M3 32-bit RISC core operating at a 72 MHz frequency, highspeed embedded memories (Flash memory up to 128 Kbytes and SRAM up to 20 Kbytes), and an extensive range of enhanced I/Os and peripherals connected to two APB buses. All devices offer two 12-bit ADCs, three general purpose 16-bit timers plus one PWM timer, as well as standard and advanced communication interfaces: up to two I2Cs and SPIs, three USARTs, an USB and a CAN.

　　The devices operate from a 2.0 to 3.6 V power supply. They are available in both the –40 to +85 °C temperature range and the –40 to +105 °C extended temperature range. A comprehensive set of power-saving mode allows the design of low-power applications.

　　The STM32F103xx medium-density performance line family includes devices in six different package types: from 36 pins to 100 pins. Depending on the device chosen, different sets of peripherals are included, the description below gives an overview of the complete range of peripherals proposed in this family.

　　These features make the STM32F103xx medium-density performance line microcontroller family suitable for a wide range of applications such as motor drives, application control, medical and handheld equipment, PC and gaming peripherals, GPS platforms, industrial applications, PLCs, inverters, printers, scanners, alarm systems, video intercoms, and HVACs.

　　STM32F103T8主要特性：

　　ARM 32-bit Cortex™-M3 CPU Core

　　– 72 MHz maximum frequency,1.25 DMIPS/MHz (Dhrystone 2.1) performance at 0 wait state memory access

　　– Single-cycle multiplication and hardware division

　　Memories

　　– 64 or 128 Kbytes of Flash memory

　　– 20 Kbytes of SRAM

　　Clock, reset and supply management

　　– 2.0 to 3.6 V application supply and I/Os

　　– POR, PDR, and programmable voltagedetector (PVD)

　　– 4-to-16 MHz crystal oscillator

　　– Internal 8 MHz factory-trimmed RC

　　– Internal 40 kHz RC

　　– PLL for CPU clock

　　– 32 kHz oscillator for RTC with calibration

　　Low power

　　– Sleep, Stop and Standby modes

　　– VBAT supply for RTC and backup registers 2 x 12-bit, 1 μs A/D converters (up to 16 channels)

　　– Conversion range: 0 to 3.6 V

　　– Dual-sample and hold capability

　　– Temperature sensor

　　DMA

　　– 7-channel DMA controller

　　– Peripherals supported: timers, ADC, SPIs,I2Cs and USARTs

　　Up to 80 fast I/O ports

　　– 26/37/51/80 I/Os, all mappable on 16 external interrupt vectors and almost all 5 V-tolerant

　　Debug mode

　　– Serial wire debug (SWD) & JTAG interfaces

　　7 timers

　　– Three 16-bit timers, each with up to 4 IC/OC/PWM or pulse counter and quadrature (incremental) encoder input

　　– 16-bit, motor control PWM timer with deadtime generation and emergency stop

　　– 2 watchdog timers (Independent and Window)

　　– SysTick timer 24-bit downcounter

　　Up to 9 communication interfaces

　　– Up to 2 x I2C interfaces (SMBus/PMBus)

　　– Up to 3 USARTs (ISO 7816 interface, LIN,IrDA capability, modem control)

　　– Up to 2 SPIs (18 Mbit/s)

　　– CAN interface (2.0B Active)

　　– USB 2.0 full-speed interface

　　CRC calculation unit, 96-bit unique ID

　　Packages are ECOPACK®

　　STM32F103T8应用：

　　motor drives

　　application control

　　medical and handheld equipment

　　PC and gaming peripherals

　　GPS platforms

　　industrial applications

　　PLCs

　　Inverters

　　Printers

　　Scanners

　　alarm systems

　　video intercoms

　　HVACs

　　图1. STM32F103T8内部方框图

　　USB to RS232 bridge方案介绍：

　　This document describes an easy and compact solution for a bridge between a standard USB port and a standard serial COM port. In modern PCs, USB is the standard communication port for almost all peripherals. However, many industrial software applications and a lot of old equipment still use the classic COM port (UART). The STEVALPCC015V1 provides a simple solution to overcome this problem. It uses the USB device as a COM port by affecting the legacy PC application designed for COM port communication.

　　USB to RS232 bridge方案特性：

　　• Demo works as a bridge between standard USB port and classic serial COM port

　　• Board implements standard CDC class of USB and emulates COM port functionality to standard USB port

　　• Board implements standard CDC class of USB and emulates COM port functionality to standard USB port

　　• Demo implements RS232 full hardware flow control using RTS and CTS

　　• STM32 medium density line device performs the communication task (bridge) between USB and RS232 (UART)

　　• Demo uses standard DB9 connector (female) to be used for RS232 and therefore the user can directly connect this demo to their PC

　　• The unit is bus-powered. Meaning it is powered by the USB bus.

　　USB to RS232 bridge方案原理图：

　　图2. USB to RS232 bridge方案原理图

　　USB to RS232 bridge方案材料清单：