ST AN2500 Application note

AN2500

Application note

ST10 electric motor control library:

SPI drivers for MP49 power board

Introduction

STMicroelectronics provides a library of motor control functions that can be used as base
blocks for motor control applications.

This application note describes the set of API to simplify the usage of the MP49 motor
control power board. It provides ST10 compatible SPI drivers to configure the board and for
diagnostic purposes.

March 2007 Rev 1 1/18

www.st.com

Contents AN2500

Contents

1 Functions set overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2 MP49 to CPU board communication overview . . . . . . . . . . . . . . . . . . . . 6

2.1 SPI interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

2.2 SPI diagnostic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2.2.1 Fault detection interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

3 API specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

3.1 Function definition for motor power board configuration . . . . . . . . . . . . . . 9

3.1.1 SetCom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

3.2 Function definitions for the motor power board diagnosis . . . . . . . . . . . . 10

3.2.1 ShortMotorDriver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

3.2.2 LowVoltPreDriver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

3.2.3 SPINGFailDetect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

3.3 Type definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

3.3.1 DIAG1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

3.3.2 DIAG2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

3.3.3 DIAG3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Appendix A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

4 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

2/18

AN2500 List of tables

List of tables

Table 1. SPI master signal description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Table 2. SPI commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Table 3. DIAG1 structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Table 4. DIAG2 structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Table 5. DIAG3 structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Table 6. Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

3/18

List of figures AN2500

List of figures

Figure 1. ST10 EMC library structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Figure 2. SPI registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Figure 3. Fault signal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

4/18

AN2500 Functions set overview

1 Functions set overview

The SPI_FS is a set of functions included in ST10 electric motor control library (see

Figure 1). It uses the ST10 peripheral SSC configured like SPI interface to allow the full

duplex communication with MP49 (slave) and to set a specific MP49 parameters
configuration or diagnosis requests, see Tabl e 2.

Figure 1. ST10 EMC library structure

ST10 EMCL

Flux

Oriented

Control

Sinusoidal

Control

Observer

Leunberger

spi.c

spi.h

SPI

Driver

Encoder

Driver

Hall sensors

Driver

Current sensing

Driver

PWM

Driver

The communication between the CPU board and the motor power board is based on SPI
interface with a chip select (4 signals in total).

The exchanged data set some parameters and the command to read the status of the motor
power board. The configuration command allows to choose the shape of fault pin output
signal. Another subset of commands allows to send diagnosis requests to read the status of
the inverter driver and of the powerMOS.

5/18

MP49 to CPU board communication overview AN2500

2 MP49 to CPU board communication overview

The MP49 motor power board communicates with the CPU board using an SPI interface
and using a fault signal to report to the CPU faults as soon as they are detected.

The MP49 requires only to be configured after reset and the CPU does not need any action
after initialization as long as the fault pin is not active.

2.1 SPI interface

The SPI interface provides a full-duplex, synchronous serial communication between
microcontrollers and peripherals. It is based upon a Master-Slave protocol where the master
is the device that drives the serial clock signal (SCLK), used to synchronize the
communication.

The SPI bus consists of four wires, Serial Clock signal (SCLK), Master Transmit / Slave
Receive (MTSR), Master Receive / Slave Transmit (MRST), and Chip Select (CS), which
carry information between the devices connected to the bus (see Figure 2).

Table 1. SPI master signal description

Name Direction Description

MTSR Output

MRST Input

SCLK Output

CS Output

Figure 2. SPI registers

SPI Serial Data Output. Serial data output from

the SPI Master to a SPI slave.

SPI Serial Data Input. Serial data input from a
SPI slave to the SPI Master.

SPI Serial Clock. Normally high, and the correct
clock pulse number is sixteen.

SPI Slave Selects. Normally high, this input
signal starts the communication when it is forced
low (for selecting the MP49 board use pin P2.7).

The SCLK control line is driven by the SPI Master and regulates the flow of data bits, so that
data is shifted on falling edge of SCLK and is sampled on the opposite edge when the data
is stable.

6/18