Microprocessor Project Required Coding

Dynamic 7- Segment Displays

Introduction

The main process of this lab is to display a combination of letters and digits with a delay of 0.5 seconds between 5, E, and A by writing a code to program the microcontroller. Then reducing the delay time to notice the difference.

Procedure

The instruction of this lab asked us to display three different characters on any three of the six 7-segment displays. This lab was very similar to our previous lab so we began with the information we already knew. Our three charters were 5,E, and A which we already knew the hexadecimal conversion. That took care of what to display, now we had to find hexadecimal numbers for which display to use. After turning the 6 displays into a 8-bit number we found the correct which to display conversion. Once we knew what and which to display we then used the knowledge discovered from the previous lab to write the code. Once the constant lines were set we entered our while loop. We needed to display 3 different outputs so we wrote the what to display and the which to display then delayed for 0.5 seconds then moved on to the next display. Once this was completed three times the while loop kept the process running allowing a sea of charters to constantly flow.

What to display	Which to display
5	0X6D	FB
E	0X79	FD
A	0X77	FE

#include <msp430.h>

int main(void)

{

P7DIR |=0xFF;// to set the direction

P8DIR |=0xFF;// to set the direction

WDTCTL = WDTPW + WDTHOLD; // stop watchdog timer

while(1)

{

P8OUT=0X6D;//what to display

P7OUT|=0x04;//High P7.2 output

P7OUT &=~0x04;//P7.2 output low

P8OUT=0xFB; // Which to display

P7OUT |= 0x08; //High

P7OUT &=~0x08;//low

_delay_cycles(50000);

P8OUT=0X79;//what to display

P7OUT|=0x04;//High P7.2 output

P7OUT &=~0x04;//P7.2 output low

P8OUT=0xFD; // Which to display

P7OUT |= 0x08; //High

P7OUT &=~0x08;//low

_delay_cycles(50000);

P8OUT=0X77;//what to display

P7OUT|=0x04;//High P7.2 output

P7OUT &=~0x04;//P7.2 output low

P8OUT=0xFE; // Which to display

P7OUT |= 0x08; //High

P7OUT &=~0x08;//low

_delay_cycles(50000);

}

return 0;

}

Results and Conclusions

We had a difficult time figuring out how to write the code and we noticed that we did not use the latch between each display. However, when we reduced the time interval between the displays, it changed so slowly. It all appeared to be displayed at the same time.

References

Lab 6 Dynamic 7-Segment Displays Manual

“MSP430F5438A” data sheet

Lab 5 Static 7-Segment Displays