special design report

Special Design ReportSpecial Design Report

IMDL Summer 2002

Matthew Chernosky

July 11, 2002

OverviewOverview

Additional hardware Pulse Width Modulation channels

Need for additonal PWM channelsDesignResults

Need for additional channelsNeed for additional channels

Atmel ATMega163 – 3 PWM channels built-in

Motion – Requires 2 channels (left and right)

Golf ball pickup– Needs more than one channel

DesignDesign

2 additional channels to be implemented

Channels used for locomotionAltera MAX7032 CPLDDevelopment in VHDL

DesignDesign

3 Settings for each channel– Forward– Reverse– Stopped

A 2-bit wide input bus selects desired setting for each channel

4 output port pins of uP

DesignDesign

AlteraMAX7032

AtmelMega163

1 MHzoscillator

MicrocontrollerCPLD

PWM A Out

PWM B Out

Chan A select

Chan B select

DesignDesign

15-bitcounter

CPLD

PWM A

PWM B

FF

FFLogic

Chan A select

Chan B select

1 MHz clock

Reset

VHDLVHDL

ENTITY motor_pwm_580 IS

PORT(

clk : in STD_LOGIC;

PWM_IN_A: in STD_LOGIC_VECTOR(1 downto 0);

PWM_IN_B: in STD_LOGIC_VECTOR(1 downto 0);

PWM_OUT_A: out STD_LOGIC;

PWM_OUT_B: out STD_LOGIC

);

END motor_pwm_580;

VHDLVHDL

cnt: PROCESS (clk)BEGIN

IF (clk = '1' and clk'EVENT) THENif (count < COUNT_MAX) then

-- increment countercount <= count + 1;

else-- reset counter when COUNT_MAX reachedcount <= COUNT_RST;

end if;END IF;

END PROCESS;

ResultsResults

Oscilliscope waveform tests

Works with servos

20 ms

1.75 ms