原标题：ST L6474+STM32F105 3D打印机解决方案

　　ST公司的即插即用3D打印机解决方案STEVAL-3DP001V1是基于L6474微步进马达驱动器和高性能32位STM32F105xx系列MCU,适用于任何3D打印机理,可驱动6轴和可编马达电流,嵌入Wi-Fi模块可控制手持社,可控制3个热点和3个风扇,支持3个加热床,支持USB和microSD外设,主要用于教学,原型机,牙齿,医疗和珠宝等行业.本文主要介绍了L6474主要特性和框图,STM32F105xx框图以及基于L6474和STM32™微步进马达开发板EVAL6474H-DISC主要特性,电路图,材料清单和PCB布局图和3D打印机解决方案STEVAL-3DP001V1主要特性和优势与框图.

　　The L6474 device, realized in analog mixed signal technology, integrates a dual low RDS(on)DMOS full bridge with all power switches equipped with an accurate on-chip current sensing circuitry suitable for non-dissipative current control and overcurrent protections. Thanks to a new current control, a 1/16 microstepping is achieved through an adaptive decay mode which outperforms traditional implementations.

　　All data registers, including those used to set analogue values (i.e.: current control value, current protection trip point, deadtime, etc.) are sent through a standard 5 Mbit/s SPI.A very rich set of protections (thermal, low bus voltage, overcurrent) makes the L6474 device “bullet proof” as required by the most demanding motor control applications.

　　L6474主要特性:

　　Operating voltage: 8 - 45 V

　　7.0 A output peak current (3.0 Ar.m.s. )

　　Low RDS(on) power MOSFETs

　　Programmable power MOS slew rate

　　Up to 1/16 microstepping

　　Current control with adaptive decay

　　Non-dissipative current sensing

　　SPI interface

　　Low quiescent and standby currents

　　Programmable non-dissipative overcurrent protection on all power MOS

　　Two-level overtemperature protection

　　L6474应用:

　　Bipolar stepper motor

　　图1.L6474框图

　　The STM32F105xx device incorporates the high-performance ARM®Cortex™-M3 32-bit RISC core operating at a 72 MHz frequency, high-speed embedded memories (Flash memory up to 256 Kbytes and SRAM 64 Kbytes), and an extensive range of enhanced I/O and peripherals connected to two APB buses. All devices offer two 12-bit ADCs, four general-purpose 16-bit timers plus a PWM timer, as well as standard and advanced communication interfaces: up to two I2Cs, three SPIs, two I2Ss, five USARTs, a USB OTGFS and two CANs.

　　The STM32F105xx operates in the -40 to +105 °C temperature range, from a 2.0 to 3.6 V power supply. A comprehensive set of power-saving mode allows the design of low-power applications.

　　The STM32F105xx offers devices in three different package types: from 64 pins to 100 pins.Depending on the device chosen, different sets of peripherals are included.

　　These features make the STM32F105xx and STM32F107xx connectivity line microcontroller family suitable for a wide range of applications such as motor drives and application control, medical and handheld equipment, industrial applications, PLCs,inverters, printers, and scanners, alarm systems, video intercom, HVAC and home audio equipment.

　　Please refer to the STM32F105xx datasheet for an overview of the complete range of peripherals proposed in this family.Please refer to the STM32F105xx reference manual RM0008 to get more information on themicrocontroller operation.The STM32F105RBT6 has a 64-pin LQFP package with 128 KBytes Flash memory and operates in the -40 to +85 °C temperature range.

　　图2.STM32F105xx框图

　　基于L6474和STM32™微步进马达开发板EVAL6474H-DISC

　　The EVAL6474H-DISC is a low cost development tool based on the L6474 and STM32™. It is an ideal starter kit for both beginners and experienced users, it is autonomous and canbe used with a software interface, or it can be used with custom firmware thanks to theembedded microcontroller with the 128 kB Flash memory and 64 kB RAM.

　　Through the available GUI the user can easily set the full configuration of application parameters.

　　There are “Plug and Play” tools suitable for high power solutions thanks to the wide operating voltage range from 8 V to 45 V and the current capability up to 3 Ar.m.s.

　　图3.微步进马达开发板EVAL6474H-DISC外形图

　　微步进马达开发板EVAL6474H-DISC主要特性:

　　DC voltage range from 8 V to 45 V

　　Maximum load phase current at 3 Ar.m.s.

　　Footprint for external resonator or crystal

　　Control interface through trimmer - user keys and switch motor input

　　Control through LED indicators

　　Interface control by USB and debug outputs

　　Compatible with SPINFamily evaluation tool

　　Autonomous board due to an embedded firmware

　　Up to 1/16 microstepping

　　Optimized layout on 2 layers board - low cost and high thermal performance

　　图4.微步进马达开发板EVAL6474H-DISC电路图:电源部分

　　图5.微步进马达开发板EVAL6474H-DISC电路图:MCU控制部分

　　图6.微步进马达开发板EVAL6474H-DISC电路图:马达控制部分

　　图7.微步进马达开发板EVAL6474H-DISC PCB顶层和底层布局图

　　微步进马达开发板EVAL6474H-DISC材料清单:

　　即插即用3D打印机解决方案STEVAL-3DP001V1

　　The STEVAL-3DP001V1 is areference design for 3D printersbased 100% on ST’s bill of materials and represents aneasy-to-use solution to jump startdriving your 3D printers.

　　Thanks to new thermoplasticmaterials and printingarchitectures, fused filamentfabrication (FFF) – the mostdiffused 3D printing technology –is progressively pervading manysectors.

　　To keep up with this innovationrace, FFF 3D printers are requiredto be intuitive, silent and fast,support multiple extruders,remotely controllable andsupport multi-zoned heated beds for large printing surfaces.

　　The STEVAL-3DP001V1 fulfills allthese requirements.

　　The STEVAL-3DP001V1 is a complete andplug-n-play solution based on an STM32 microcontroller (32-bit ARM® Cortex®-M4core) running the open-source Marlin firmware.

　　The prints can be performed via the UART,microSD or Wi-Fi interfaces.The STEVAL-3DP001V1 supports up to3 extruders with its low-noise and highprecision

　　L6474 motor drivers, eachprogrammable to deliver up to 3 A.

　　The board is able to control up to 3 hotends and 3 fans thanks to 6 embedded low RDS(on) MOSFETs and provides 3 additionalhigh-current (32 A) heater drivers, fitting the need for temperature-controlled multizoneheated beds. The STEVAL-3DP001V1 features integrated Wi-Fi connectivity,enabling the user to drive a 3D printer usinga smartphone or tablet.

　　For each of the six axes, a digital endstop input is provided allowing the use ofpositioning sensors; up to two per X, Y andZ axis if necessary. Mechanical, optical ormagnetic sensors are supported and theboard can also power them.

　　Moreover, the board includes a completedebugging solution (STLINK-V2), a toolappreciated by developers. The STEVAL-3DP001V1 allows connections to another board, for example the Raspberry Pi,offering features including a user-friendlyweb interface, easy firmware upgrades orcontrolling the printing progress using acamera.

　　图8.3D打印机解决方案STEVAL-3DP001V1外形图

　　3D打印机解决方案STEVAL-3DP001V1主要特性和优势:

　　• Adaptable to any 3D printer mechanics

　　• Based on open-source Marlin firmwarerunning on STM32

　　• Driving up to 6 axes (3 extruders) withprogrammable motor currents via firmware

　　• Controllable by portable devices thanks toembedded Wi-Fi module

　　• Controlling up to 3 hot ends and 3 fans

　　• Supports up to 3 heated beds

　　• Easy firmware customization thanksto embedded debugging tool andOpenSTM32 environment

　　• USB and microSD peripheral support

　　图9. 3D打印机解决方案STEVAL-3DP001V1框图