One day-workshop on tms320 f2812

One Day Workshop on
TMS320F2812

Outline
 Block Diagram of Motor Control
 Requirement of Inverters
 Introduction to TMS320F2812
 Creating linker command file
 System Initialization
 LED Blinking
 PWM Module

© 2008 Pantech Solutions™ | All rights reserved | www.panetchsolutions.net

Three Phase Inverter

AC M

Input
Source Rectifier Filter Load
PFC Inverter


Inverter Requirement from Processor

 The increase of control points demands more outputs of PWM and more
accurate output.
 Rectifier control 4-6
 PFC control 1-2
 DC-DC Control, Brake control(optional) 1
 Inverter 6
 Complex control algorithm requires more powerful processing ability:
 Higher performance floating point computation, quicker cycle clock,
 Longer instruction Word,
 parallel processing,
 deep pipelines.


Features of TMS320F2812
 High-Performance 32-Bit CPU
 16 x 16 and 32 x 32 MAC Operations
 16 x 16 Dual MAC
 On-Chip Memory
 Flash Devices: Up to 128K x 16 Flash
 ROM Devices: Up to 128K x 16 ROM
 1K x 16 OTP ROM
 L0 and L1: 2 Blocks of 4K x 16 Each SARAM.
 External Interface
 Up to 1M Total Memory
 Three Individual Chip Selects
 Three External Interrupts
 Three 32-Bit CPU-Timers
 Motor Control Peripherals
 Two Event Managers


Features
 Serial Port Peripherals
 Serial Peripheral Interface
 Two Serial Communications Interfaces
 Enhanced Controller Area Network
 Multichannel Buffered Serial Port

 12-Bit ADC, 16 Channels
 2 x 8 Channel Input Multiplexer
 Two Sample-and-Hold
 Single/Simultaneous Conversions
 Fast Conversion Rate: 80 ns/12.5 MSPS

 Up to 56 General Purpose I/O (GPIO) Pins


Linker Function
Allocate the sections into the target configured
memory map.
Relocate the symbol and sections to assign them into
final address.
Resolved the undefined external references between
input files.

Memory Map
 MEMORY
The MEMORY directive allows you to define the memory
map of a target system. You can name portions of memory
and specify their starting addresses and their lengths.
 SECTIONS
The SECTIONS directive tells the linker how to combine
input sections into output sections and where to place these
output sections in memory.

Function
 Memory Map Description
 Name
 Location
 Size
 Sections Description
 Directsoftware section into named memory regions
 Allows per file discrimination
 Allows separate load/run locations

Compiler Section Names

Initialized Sections
Name Description Link Location
.text code FLASH
.cinit initialized global and FLASH
static variables
.econst constant data FLASH
(e.g. const int k = 3;)
.switch tables for switch statements FLASH
.pinit tables for global constructors (C++) FLASH

Uninitialized Sections
Name Description Link Location
.ebss global & static variables RAM
.stack stack space low 64Kw RAM
.esysmem memory for malloc functions RAM

Sections

Global Variable(.ebss)
 int x = 2; Init Variables(.cinit)
 int y = 7;

 Void main(void)
{
long z; Local Variable(.stack)

z=x+y; Code(.text)

}

Example

0x00 0000 M0SARA 0x00 0400 M1SARA
M M
0x400 0x400

0x00 8000 L0SARA 0x00 9000 L1SARA
M M
0x1000 0x1000

0x30 0000 FLASH
0x4000
Placement Sections

.text into FLASH Block on PAGE 0
.ebss into MOSARAM on PAGE 1
.cinit into FLASH Block on PAGE 0
.stack into MOSARAM on PAGE 1

Linker Command File

MEMORY
{
PAGE 0: /* Program Memory*/
FLASH: origin = 0x300000, length = 0x40000
PAGE 1: /* Data memory */
M0SARAM: origin = 0x000000, length = 0x400
L0SARAM: origin = 0x008000, length = 0x1000
L1SARAM: origin = 0x009000, length = 0x1000
}
SECTIONS
{
.text: > FLASH PAGE = 0
.ebss: > M0SARAM PAGE = 1
.cinit: > FLASH PAGE = 0
.stack > M1SARAM
}

Summary
 Memory Mapping
 Linker Command File

System Initialization

 Oscillator, PLL and Clocking mechanisms,
 Watchdog function and Low Power Mode

OSC and PLL Block

PLL and On chip oscillator provides the clocking signals for the device
and as well as control the Low Power Mode entry

XCLKIN OSCCLK PLL Diabled
0
On-
Chip CPU
OSC PLL /2 1
Bypass SYSCLKOUT

PLL

PLL Blok
4-bit PLL Select

PLLCR Value


Watchdog Module
 Resets the C28x if the CPU crashes
 Watchdog counter runs independent of CPU
 If counter overflows, reset or interrupt is
triggered
 CPU must write correct data key sequence to
reset the counter before overflow.
 Watchdog must be serviced (or disabled)
within ~4.37ms after reset (30 MHz OSCCLK
for 150 MHz device)

Low-Power Modes Block

 IDLE Mode - XNMI
 STANDBY Mode - Any GPIOA
 HALT Mode - XRS and GPIOA

Summary
 Clocking information
 Watch dog module
 Low Power Module description

Example 1
 Linker Command File


ON CHIP MEMORY
0x00 0000 M0SARA 0x00 B000 L3SARA
M M
0x400 0x1000

0x00 0400 M1SARA 0x00 C000 L4SARA
M M
0x400 0x1000
System Description
TMS320F28335 0x00 8000 L0SARA 0x00 D000 L5SARA
M M
0x1000 0x1000

0x00 9000 L1SARA 0x00 E000 L6SARA
M M
0x1000 0x1000

L2SARA L7SARA
0x00 A000 0x00 F000
M M
0x1000 0x1000

Memory Placement section

.text into RAM Block L0123SARAM on PAGE 0 (PRG Memory)
.ebss into RAM Block L0123SARAM on PAGE 1(Date Memory)
.cinit into RAM Block L0123SARAM on PAGE 0 (PRG Memory)
.stack into RAM Block M1SARAM on PAGE 1 (Date Memory)

Memory Mapping

MEMORY
{
PAGE 0: /* Program Memory*/
L0123SARAM: Origin = 0x008000, length = 0x4000
PAGE 1: /* Data memory */
L4SARAM: origin = 0x00C000, length = 0x1000
L5SARAM: origin = 0x00D000, length = 0x1000
L6SARAM: origin = 0x00E000, length = 0x1000
L7SARAM: origin = 0x00F000, length = 0x1000
}
SECTIONS
{
.text: > L0123SARAM PAGE = 0
.ebss: > L4SARAM PAGE = 1
.cinit: > L0123SARAM PAGE = 0
.stack: > M1SARAM PAGE =1
.reset: > L0123SARAM PAGE =0,TYPE = DSECT
}

Example 2
 LED Blinking Program

 The objective of this example is to toggle the
LED with particular interval
 Define PORTA as the output port.(GPIO 0:31)


Procedure
 Step 1. Initialize System Control
 Step 2. Initalize GPIO
 Step 3. Clear all interrupts and initialize PIE
vector table
 Step 4. Initialize all the Device Peripherals
 Step 5. User specific code


System Initialization


Initialize the PLL
 Initialize the PLLCR Value.
 Initialize the PLLSTS Value.
 Assign the clock value for Peripheral Devices.


GPIO configuration
 Plan the device pin-out(GPIOA…etc)
 GPIOA
 Select the pin function
 INPUT/OUTPUT
 GpioCtrlRegs.GPAMUX1.all = 0x0000; // GPIO functionality GPIO0-GPIO15
 GpioCtrlRegs.GPAMUX2.all = 0x0000; // GPIO functionality GPIO16-GPIO31

 Select the pin direction
 OUTPUT
 GpioCtrlRegs.GPADIR.all = 0x0000; // GPIO0-GPIO31 are inputs

 For LED blinking
 GpioDataRegs.GPADAT.all =0xFFFFFF;
 CALL DELAY
 GpioDataRegs.GPADAT.all =0x000000;
 CALL DELAY


Pulse for Constant 120° Mode

1 1 0 0 0 0
For(;;)
{
1 1 0 0 GpioDataRegs.GPADAT.all =0x00000021;
DELAY_US(3333);
GpioDataRegs.GPADAT.all =0x00000003;
DELAY_US(3333);
0 0 1 1 0 0 GpioDataRegs.GPADAT.all =0x00000006;
DELAY_US(3333);
GpioDataRegs.GPADAT.all =0x0000000C;
0 0 0 1 1 0 DELAY_US(3333);
DELAY_US(3333);
DELAY_US(3333);
}
1 0 0 0 0 1


Pulse for Constant 180° Mode

1 1 1 0 0 0
For(;;)
{
DELAY_US(3333);
DELAY_US(3333);
DELAY_US(3333);
GpioDataRegs.GPADAT.all =0x0000000E;
0 0 0 1 1 1 DELAY_US(3333);
GpioDataRegs.GPADAT.all =0x0000001C;
DELAY_US(3333);
DELAY_US(3333);
}
1 1 0 0 0 1


Pulse Width Modulation

 PWM is a scheme to represent a signal as a
sequence of pulses
 fixed carrier frequency
 fixed pulse amplitude
 pulse width proportional to instantaneous signal
amplitude
 PWM energy ≈ original signal energy

Flexible PWM generation
 Multiple PWM outputs with programmable
polarity.
 Multiple independent PWM outputs from same
time base.
 Individual trip zones for fault management.
 Dead-band and chopping operation.
 Shadow loading for glitch free operation.

W hy Use PWM
Techniques
 To control inverter output frequency
(fundamental)
 To control inverter output voltage
(fundamental)
 To minimize harmonic distortion


PWM Period & Frequency Calculator

 PWM period = (TBPRD + 1 ) * TTBCLK for up counter.
 PWM period = 2 x TBPRD * TTBCLK for UPDOWN


Event Manager
 For
 Motion control and Motor control applications
 Modules
 GP Timers
 PWMs
 QEP
 Capture Units
 Types
 EVA
 EVB

Event Manager Signals
EVA EVB
Modules
Module Signal Module Signal
GP Timer 1 T1PWM/T1CMP GP Timer 3 T3PWM/T3CMP
GP Timers
GP Timer 2 T2PWM/T2CMP GP Timer 4 T4PWM/T4CMP
Compare 1 PWM1/2 Compare 4 PWM7/8
Compare Modules Compare 2 PWM3/4 Compare 5 PWM9/10
Compare 3 PWM5/6 Compare 6 PWM11/12
Capture 1 CAP1 Capture 4 CAP4
Capture Modules Capture 2 CAP2 Capture 5 CAP5
Capture 3 CAP3 Capture 6 CAP6
QEP1 QEP3
QEP Units QEP QEP2 QEP QEP4
QEPI1 QEP12
Timer- TDIRA Timer- TDIRB
direction direction
External Timer Interrupts
external external
clock TCLKINA clock TCLKINB
C1TRIP C4TRIP
External Compare Output Compare C2TRIP Compare C5TRIP
C3TRIP C6TRIP
T1CTRIP/ T3CTRIP/
External Trip Inputs
T2CTRIP T4CTRIP
© 2008 Pantech Solutions™ | All rights reserved |
www.panetchsolutions.net

General-Purpose (GP) Timers
 Two nos of Timers in Each EV
 Registers
 TxCNT Counter Register
 16-bit
 TxCMPR Compare Register
 16-bit, Double Buffered and Shadow Register
 TxPR Period Register
 16-bit, Double Buffered and Shadow Register
 TxCON Timer Control Register
 TDIRx Direction Register

PWM Characteristics
 16-bit registers
 Wide range of programmable dead band for the PWM output pairs
 Change of the PWM carrier frequency for PWM frequency wobbling as
needed.
 Change of the PWM pulse widths within and after each PWM period as
needed.
 External-maskable power and drive-protection interrupts.
 Pulse-pattern-generator circuit, for programmable generation of asymmetric,
 symmetric, and eight-space vector PWM waveforms.
 Minimized CPU overhead using auto-reload of the compare and period
registers.


Generating PWM
 Step1
 Select Event Manager
 EVA or EVB or both;
 Step2
 Initialize the Timer1
 Period
 Compare
 Counter
 Step3
 Initialize the Timer2
 Period
 Compare
 Counter


Generating PWM
 Step4
Initialize the General purpose Timer Control
Register A
 Step5
Enable Compare Register
 Step6
Setup compare action control register


Example Code
EvaRegs.T1PR = 0xFFFF; // Timer1 period
EvaRegs.T1CMPR = 0x3C00; // Timer1 compare
EvaRegs.T1CNT = 0x0000; // Timer1 counter
EvaRegs.T1CON.all = 0x1042;
EvaRegs.T2PR = 0x0FFF; // Timer2 period
EvaRegs.T2CMPR = 0x03C0; // Timer2 compare
EvaRegs.T2CNT = 0x0000; // Timer2 counter
EvaRegs.T2CON.all = 0x1042;
EvaRegs.GPTCONA.bit.TCMPOE = 1;
EvaRegs.GPTCONA.bit.T1PIN = 1;
EvaRegs.GPTCONA.bit.T2PIN = 2;

EvaRegs.CMPR1 = 0x0C00;
EvaRegs.CMPR2 = 0x3C00;
EvaRegs.CMPR3 = 0xFC00;

EvaRegs.ACTRA.all = 0x0666;
EvaRegs.DBTCONA.all = 0x0000; // Disable deadband
EvaRegs.COMCONA.all = 0xA600;


Advancement of PWM
features in DSP processor


EPWM Block

Time-base (TB) module

Counter-compare (CC)
module
Action-qualifier (AQ) module

Dead-band (DB) module

PWM-chopper (PC) module

Event-trigger (ET) module

Trip-zone (TZ) module

AQ Function


EPWM Count Up Asymmetric Waveform
with Independent Modulation on EPWMA / B

Motivation for Dead-Band
Supply Rail

Gate Signal
Complementary PWM To power
Switching Device

Transistor gates turn on faster than they shut off
Short circuit if both gates are on at same time!

ePWM Event-Trigger Interrupts and SOC

High Resolution PWM (HRPWM)
PWM Period
Regular PWM
Device Clock Step
(i.e. 100MHz)
(i.e. 10ns)

HRPWM divides a clock Calibration Logic tracks the
cycle into smaller steps number of Micro Steps per
ms ms ms ms ms ms
called Micro Steps clock to account for
(Step Size ~= 150ps) Calibration Logic variations caused by
Temp/Volt/Process

HRPWM
Micro Step (~150ps)

References
1.http://www-k.ext.ti.com/sc/technical_support/knowledgebase.htm
2.TMS320x2833x, 2823x Enhanced Pulse Width Modulator (ePWM) Module
3.TMS320C28x Assembly Language Tools v5.0.0
4.TMS320C28x CPU and Instruction Set Reference Guide
5. TMS320F28335/28334/28332 TMS320F28235/28234/28232 Digital Signal Controller
6.www.pantechforum.com


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