EENG 383

Lab 3 - Music Box with Timers

Lab:	3
Status	Live

InLab 3

Some self-guided activities.

Lab 3 assignment

You may work in teams of one or two.

Lab assignment

Build an embedded system which plays a song every time the upper button is pressed.

Note If you have an existing configuration (say from the inlab03) that you want to copy over to a new project (say for your lab03), then:

Copy the xxx.mc3 file (from your inlab03) into the main directory of the new project (lab03),
In the project manager area of the new project (lab03) add the xxx.mc3 file into the Important Files folder (in the project navigator window) by right clicking and selecting "Add Item to Important Files...",
Open the Microchips code configurator,
The inlab03 configuration will load,
Edit the (inlab03) configuration as needed,
Generate the MCC support files.

Program Requirements

A whole note should take 1 second, half note 0.5 seconds, and so on,

Have a 32^nd rest between notes,

Use Timer 1 with a 1:1: prescaler to generate the note frequencies,

Store at least two octaves worth of notes (half periods of timer 1) in an array called scale. For example, my code has the following (partial) declaration:
uint16_t scale[NUM_OCTAVES*12] = {12864,12144,11472,10816,10208,9632,…
Note, I used a #define to set NUM_OCTAVES to 2,

Use Timer 0 with a 1:256 prescaler to generate the note durations,

Store your song in two arrays, one for notes and one for duration,

The array storing the notes of the song should have the index of the scale of each note. For example, my code which plays Hot Crossed Buns, has the following (partial) declaration:
uint16_t notes[SONG_LENGTH] = {B5, A5, G4, B5, A5,…
The symbols in the notes array "B5", "A5", etc. are #defined to indicies in the scale array which contains the half period of that note. For example, since the half period of a G4 note is 10208 timer 1 counts (which is index 4 in the scale array defined above), my code contains the following #define at the top of the program:
#define G4 4
The array storing the duration of the notes of the song, For example my code has the following (partial) declaration:
uint16_t duration[SONG_LENGTH] = {QUA, QUA, HAL, QUA,…
The symbols in the duration array, "QUA", "HAL" are #define to the number of 1:256 prescaled timer 0 counts each duration required. For example, a quarter note is 0.25 seconds long, corresponding to 15625 counts on a 1:256 prescaled timer 0. So my code contains the following define:
#define QUA 15625

Set the speaker pin to logic 0 when you are not playing a note,

Use the MCC functions to:

write the timers,
check if the timer has overflowed,
read the button, and
toggle speaker pin.

Do not use the TMR1_ReadTimer or TMR0_ReadTimer functions.

Verification:
Play the notes of a song with at least 12 notes and that includes at least 2 different note durations.

Turn-in

You may work with a single partner (or alone) to complete this lab. Submit your main.c file on Canvas using the instructions posted there. You should take note of the Rubric that will be used to evaluate your assignment. Please form a group before submitting using the instructions posted on Canvas. You will demonstrate your code at the beginning of lab.