原标题：NXP PCA9629A步进马达控制解决方案

　　nxp公司的PCA9629A是I2C总线控制的低功耗CMOS器件,为驱动四相步进马达提供了所需的所有逻辑和控制特性.四个平衡的推挽输出可提供25 mA电流,无缝连接到外接大电流驱动器.高达1000pF负载和100 ns上升和下降时间,内置1MHz振荡器不需要外接元件,主要用于消费类家用电器或玩具,工业自动化,HVAC和建筑物环境控制系统,变速风扇和泵,零售终端,游戏机等.本文介绍了PCA9629A主要特性和优势,框图和步进马达控制框图,以及OM13285步进马达控制板Rev. 2.2电路图.

　　The PCA9629A is an I2C-bus controlled low-power CMOS device that provides all the logic and control required to drive a four phase stepper motor. PCA9629A is intended to be used with external high current drivers to drive the motor coils. The PCA9629A supports three stepper motor drive formats: one-phase (wave drive), two-phase, and half-step. In addition, when used as inputs, four General Purpose Input/Outputs (GPIOs) allow sensing of logic level output from optical interrupter modules and generate active LOW interrupt signal on the INT pin of PCA9629A. This is a useful feature in sensing home position of motor shaft or reference for step pulses. Upon interrupt, the PCA9629A can be programmed to automatically stop the motor, re-start motor, enable extra steps or reverse the direction of rotation of motor.

　　Output wave train is programmable using control registers. The control registers are programmed via the I2C-bus. Features built into the PCA9629A provide highly flexible control of stepper motor, off-load bus master/micro and significantly reduce I2C-bus traffic.

　　These include control of step size, number of steps per single command, number of actions from 1 to 255 or continuous rotations and direction of rotation. Re-start motor for new speed and operation without waiting for motor stop. A ramp-up on start and/or ramp-down on stop is also provided with re-enable ramp-up or ramp-down to change the ramp rate curve on the fly.

　　The PCA9629A is available in a 16-pin TSSOP package and is specified over the -40 degreeC to +85 degreeC industrial temperature range.

　　PCA9629A主要特性和优势:

　　 Generate motor coil drive phase sequence signals with four outputs for use with external high current drivers to off-load CPU

　　 Four balanced push-pull type outputs capable of sinking 25 mA or sourcing 25 mA for

　　glueless connection to external high current drivers needed to drive unipolar stepper motor coils

　　 Up to 1000 pF loads with 100 ns rise and fall times

　　 Built-in 1 MHz oscillator requires no external components

　　 Stepper motor drive control logic

　　 One-phase (wave drive), two-phase, and half-step drive format logic level outputs

　　 Programmable step rate: 333.3 kpps to 0.3 pps with 3 % accuracy

　　 Programmable ramp-up on start and ramp-down to stop

　　 Programmable re-enable ramp-up or ramp-down to change ramp rate curve on the fly

　　 Programmable re-start motor with new speed and operation while motor is still running

　　 Programmable motor action either multiple times (1 to 255) or continuously

　　 Programmable loop delay timer for motor reversal mode

　　 Programmable steps with clockwise and/or counter-clockwise control

　　 Direction control of motor shaft

　　 Selectable active hold (last state), power on, power off or released states for motor

　　shaft

　　 32-bit step counter to count output steps

　　 Interrupt features

　　 Active LOW open-drain interrupt output

　　 Programmable watchdog timer with option to generate interrupt, reset device or

　　stop motor

　　 Programmable motor stop interrupt

　　 Sensor enabled drive control: linked to interrupt from GPIO pins

　　 Programmable interrupt Mask Control for input sources

　　 Four stepper motor drive outputs: OUT0 to OUT3

　　 Configured to drive stepper motor outputs and capable to read back the last output

　　states when motor is stopped

　　 Both output phase and state can be changed at any time

　　 Programmable time-out timer to set all outputs to zeros when motor is stopped

　　 Configured as general purpose outputs to drive (source/sink) loads up to 25 mA

　　 Four general purpose I/Os: P0 to P3

　　 Configured to sense logic level outputs from optical interrupter photo transistor

　　circuit

　　 Programmable filter timer to suppress spike or noise for P0 and P1 inputs

　　 Configured as outputs to drive (source/sink) LEDs or other loads up to 25 mA

　　 4.5 V to 5.5 V operation

　　 1 MHz Fast-mode Plus (Fm+) compatible I2C-bus serial interface with 30 mA

　　high drive capability on SDA output for driving high capacitive buses

　　 Active LOW reset (RESET) input pin resets device to power-up default state: can be

　　used to recover from bus stuck condition

　　 All Call address allows programming of more than one device at the same time with

　　the same parameters

　　 16 programmable slave addresses using two address pins

　　 40 C to +85 C operation

　　 ESD protection exceeds 2000 V HBM per JESD22-A114 and 1000 V CDM per

　　JESD22C101

　　 Latch-up testing is done to JEDEC Standard JESD78 which exceeds 100 mA

　　 Package offered: TSSOP16

　　PCA9629A应用:

　　 Amusement machines

　　 Gaming and slot machines

　　 Consumer home appliances or toys

　　 Industrial automation

　　 HVAC and building climate control systems

　　 Robotics

　　 Security and surveillance camera

　　 Variable-speed fans and pumps

　　 Vending machines

　　图1. PCA9629A框图

　　图2. PCA9629A步进马达控制框图

　　PCA9629A demo kit (OM13285) is designed to let customers evaluate the PCA9629A in a realistic application. The demo kit includes a stepper motor board with sensors and the stepper motor demo board with a number of pre-defined functions. The functions are executed by pressing push-button switches on the demo board.

　　The PCA9629A Stepper Motor Controller Demo Board is designed to let customers evaluate the PCA9629A in a realistic application. The demo board kit includes a Stepper Motor board with sensors and the Stepper Motor Demo Board with a number of pre-defined functions. The parameters used by these functions can be easily changed by changing a configuration header file. To customize the application further, the generalized driver functions used in the demo firmware can be easily modified with a free compiler tool, lpcXpresso, available at: www.lpcware.com/lpcxpresso.

　　图3. OM13285 PCA9629A步进马达控制板Rev. 2.2外形图