Datasheet

1. General description
The PCA9629A is an I
2
C-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 I
2
C-bus. Features built into the PCA9629A provide highly flexible
control of stepper motor, off-load bus master/micro and significantly reduce I
2
C-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 Cto +85C industrial temperature range.
2. Features and benefits
 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
PCA9629A
Fm+ I
2
C-bus advanced stepper motor controller
Rev. 2 — 21 March 2014 Product data sheet