EVAL6207N Datasheet, PDF (5/34 Pages) STMicroelectronics – PractiSPIN evaluation system configuration and set up guide

AN1794
1
System overview
System overview
To illustrate the operation of the practiSPIN system, we will look at one typical device
supported by the system.
The L6207 includes two independent full or H bridges with separate logic inputs and current
control functions.
The two bridges are designated A and B and their output pins designated as OUT1A,
OUT2A, OUT1B, and OUT2B. These outputs are controlled independently by logic inputs
IN1A, IN2A, IN1B, and IN2B respectively.
A logic high or low on any of these inputs will drive its corresponding output to the positive
supply rail or to ground. Both of the A outputs will be forced to an off (high impedance) state
if the ENA pin is taken logic low, as will the B outputs if ENB is taken low. The L6207 is thus
controlled by six logic inputs: IN1A, IN2A, and ENA controlling bridge A and IN1B, IN2B, and
ENB controlling bridge B. Each bridge also has an analog control signal, VREFA and
VREFB, which control the current.
1.1
Target board
The L6207 target board gives access to the bridge A and B outputs at connectors CN3 and
CN4 respectively.
When driving a stepper motor, the two wires from one of the motor windings will connect to
CN3 and the other winding will connect to CN4. Swapping between the two connectors or
swapping the polarity at a given connector will only reverse the sense of motor direction. DC
supply power in the range of 12 to 48 Vdc is connected at CN1. The polarity marked on the
board silkscreen must be strictly observed! The eight control signals are taken from the 34-
pin ribbon header (CN5) and are driven by the control interface PCB via a short flat cable.
1.2
Control interface board
The control interface PCB is based on an ST72F264 microcontroller. The micro includes a
UART and communicates with the practiSPIN software via 9 pin D connector P1 employing
a standard RS232 interface.
The micro is based on flash memory and its firmware includes a write protected boot-loader
routine that allows the practiSPIN software to update or change the operating program in the
ST7 as required for different target boards. 5 Vdc power for the board is received via the 34-
pin ribbon cable from the target board or can be directly supplied at J2 if jumper WJ1 is
removed. The eight control signals for the target board are generated by the ST7 micro. The
six logic signals are generated directly by six of the eight pins of port B while the two analog
current references (VREFA and VREFB) are generated by pulse width modulated (PWM)
signals generated by the ST7 along with an offset adjusting circuit controlled by
potentiometer R18.
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