User manual

LPCXpresso Experiment Kit - User’s Guide

Page 52

Run the program and enter five characters and then hit enter. What happens?

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The reason for this is that there is a queue on the LPCXpresso side. Each time getchar() is called om

the microcontroller side, a character is removed from the queue.

Also note that text written by the user is printed in green color and text from the target system (i.e., the

LPC111x) is printed in black color.

The blocking implementation of the read functions limits the usefulness. A final application would never

use this functionality. It would simply not be practical to always have the LPCXpresso IDE connected

to the system. It can however be a very useful functionality when debugging. The application can for

example ask the user at startup if special settings shall be used. The user can then quickly test several

settings without having to recompile the application.

As an extra experiment, create a program that reads input from the console and converts it to a

number. Check that only digits are entered and that the final number is within the range of a 32-bit

number.