Arduino uno User Manual

To transfer the string into flash memory, we use the PSTR macro. It ensures
that the strings we output using printPGM will be copied to flash memory when
the program gets compiled.
Writing the Game Loop
The most central function of our game is update_game . It implements the actual
game loop and first clears the screen by calling clear_screen . Then it uses
draw_circle to draw the current target. move_crosshairs calculates the new position
of the crosshairs depending on the player’s movement. draw_crosshairs outputs
the crosshairs to the screen.
check_target determines the state of the current target—in other words, it checks
whether the user has hit the target, whether the target has been on the screen
for too long, or whether nothing special has happened. If all targets have been
shown already, the game is over.
To control the crosshairs, we use the following helper functions:
Tinkering/Pragduino/Pragduino.ino
void move_crosshairs() {
if (left) chx -= chvx;
if (right) chx += chvx;
if (up) chy -= chvy;
if (down) chy += chvy;
if (chx <= CH_LEN)
chx = CH_LEN + 1;
if (chx >= WIDTH - CH_LEN)
chx = WIDTH - CH_LEN - 1;
if (chy <= CH_LEN)
chy = CH_LEN + 1;
if (chy >= HEIGHT - CH_LEN)
chy = HEIGHT - CH_LEN - 1;
}
void draw_crosshairs() {
tv.draw_row(chy, chx - CH_LEN, chx - 1, WHITE);
tv.draw_row(chy, chx + 1, chx + CH_LEN, WHITE);
tv.draw_column(chx, chy - CH_LEN, chy - 1, WHITE);
tv.draw_column(chx, chy + 1, chy + CH_LEN, WHITE);
}
move_crosshairs checks all global variables related to the current Nunchuk state.
It updates the position of the crosshairs depending on the variable values.
Then it ensures that the crosshairs stay within the screen’s bounds.
Chapter 9. Tinkering with the Wii Nunchuk • 160
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Arduino uno Specifications

General

Form factor	Arduino
Certification	RoHS, FC, CE
Processor model	-
Processor frequency	- MHz
Microcontroller model	ATmega328
Microcontroller frequency	16 MHz
DC input voltage	7-12 V
Operating voltage	5 V
DC current per I/O pin	40 mA
Flash memory	0.032 MB
Maximum internal memory	- GB
SRAM (Static Random Access Memory)	2 KB
EEPROM (Electrically Erasable Programmable Read-Only Memory)	1 KB
Wi-Fi	No
Number of analog I/O pins	6
Number of digital I/O pins	14

Weight and Dimensions

Board dimensions	53.4 x 68.6 mm