1. EE 319K Introduction to Embedded Systems
2-D Arrays, Bitmaps, Sprites, Game Engines

2. Agenda Agenda Software design 2-D array Bitmaps Wav Files Game Engines
Lab 9

3. Software Design Modular programming Make it easier to understand
Each screen is a complete story without scrolling
Maximize the number of modules
Minimize the interdependency
Bandwidth of data passed from one to another
Control coupling: actions in one cause effects in another
Shared variables (very bad)
Book Section 5.2

4. Software Design Design for test Manage resources
Consider how it will be tested while designing
Module has three files
Header: What the module does
Code: How it works
Test: A main program used to test the module
Manage resources
LCD graphics
Time (processor cycles)
A fun game requires careful control of time
Input/Output
Switches, slide pot, DAC, LCD

5. 2-D Array or Matrix What: 2 rows and 3 columns, 8 bits each Why:
unsigned char M[2][3];
Why:
Images
Maps
How: (C uses row major)
C code to access M[i][j] = 5;
Write this in assembly (R0=i, R1=j)
i = row
j = column
n= # of columns
Base+n*i+j
Base+2*(n*i+j)
Base+4*(n*i+j)
Num of bytes/element

6. 2-D Array or Matrix j i Base+2*(7*i+j) What: 6 rows and 7 columns Why:
short Connect4[6][7];
Why:
Images
Maps
How: (row major)
Write C code to set array values to 0 i
Base+2*(7*i+j)

7. 2-D Array or Matrix j i Assuming C[6][7] // check the rows
for(i=0;i<6;i++){
for(j=0;j<4;j++){
if((C[i][j]==1)
&&(C[i][j+1]==1)
&&(C[i][j+2]==1)
&&(C[i][j+3]==1)){
Iwin(); } i
0 means free
1 means me
-1 means you

8. Nokia 5110 Graphics Format Column 0 Row 0 Row 48
LCD is 48 rows, 84 columns, 1 bits/pixel
Column 84

9. BMP File Format Sprites as objects moving across screen
Sprites are monochrome W pixels wide by H pixels high

10. BMP File Format 16 wide, 10 high Placed at x=48, y=24 F F F F
Nokia5110_PrintBMP(48,24,SmallEnemy10pointA,0);
16 wide, 10 high
Placed at x=48, y=24
F F
F F
FFFFFFFFFF
FFFFFFFFFFFF
FFF FFFF FFF
F FFFFFFFF F
F F F F
The raw data from BMP file to illustrate how the image is stored (0s replaced with spaces).

11. BMP File Format Example BMP file written as C constant Header (w x h)
const unsigned char Enemy10Point1[] = {
0x42,0x4D,0xC6,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x76,0x00,0x00,0x00,0x28,0x00,
0x00,0x00,0x10,0x00,0x00,0x00,0x0A,0x00,0x00,0x00,0x01,0x00,0x04,0x00,0x00,0x00,
0x00,0x00,0x50,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x80,0x00,0x00,0x80,
0x00,0x00,0x00,0x80,0x80,0x00,0x80,0x00,0x00,0x00,0x80,0x00,0x80,0x00,0x80,0x80,
0x00,0x00,0x80,0x80,0x80,0x00,0xC0,0xC0,0xC0,0x00,0x00,0x00,0xFF,0x00,0x00,0xFF,
0x00,0x00,0x00,0xFF,0xFF,0x00,0xFF,0x00,0x00,0x00,0xFF,0x00,0xFF,0x00,0xFF,0xFF,
0x00,0x00,0xFF,0xFF,0xFF,0x00,
0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
0x00,0x0F,0x00,0x00,0x00,0x00,0xF0,0x00,
0x00,0x00,0xF0,0x00,0x00,0x0F,0x00,0x00,
0x00,0x0F,0xFF,0xFF,0xFF,0xFF,0xF0,0x00,
0x00,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0x00,
0x00,0xFF,0xF0,0xFF,0xFF,0x0F,0xFF,0x00,
0x00,0xF0,0xFF,0xFF,0xFF,0xFF,0x0F,0x00,
0x00,0xF0,0x0F,0x00,0x00,0xF0,0x0F,0x00,
0xFF };
Example BMP file written as C constant
Header (w x h)
Pixel data
We use 4-bit BMP but all values above a threshold are deemed 1 for monochrome.

12. BMP Header Format

13. Timer 2A Periodic interrupt
Resolution: bus period
Precision: 32 bits
Max period: 53 sec (80 MHz)
0) activate timer2 clock
1) disable timer2A
2) Precision to 32 bits
3) periodic mode
4) TAILR value
5) clock resolution
6) clear timeout flag
7) arm timeout
8) priority 4
9) enable in NVIC
10) enable timer2A

14. 77 total INTERRUPT VECTORS Lab 7 Lab 8 Lab 9 Vector address Number IRQ
ISR name in Startup.s
NVIC
Priority bits 0x 14 -2
PendSV_Handler
NVIC_SYS_PRI3_R
23 – 21
0x C 15 -1
SysTick_Handler
31 – 29 0x 16
GPIOPortA_Handler
NVIC_PRI0_R
7 – 5 0x 17 1
GPIOPortB_Handler
15 – 13 0x 18 2
GPIOPortC_Handler
0x C 19 3
GPIOPortD_Handler 0x 20 4
GPIOPortE_Handler
NVIC_PRI1_R 0x 21 5
UART0_Handler 0x 22 6
UART1_Handler
0x C 23 7
SSI0_Handler 0x 24 8
I2C0_Handler
NVIC_PRI2_R 0x 25 9
PWMFault_Handler 0x 26 10
PWM0_Handler
0x C 27 11
PWM1_Handler 0x 28 12
PWM2_Handler
NVIC_PRI3_R 0x 29 13
Quadrature0_Handler 0x 30
ADC0_Handler
0x C 31
ADC1_Handler 0x 32
ADC2_Handler
NVIC_PRI4_R 0x 33
ADC3_Handler 0x 34
WDT_Handler
0x C 35
Timer0A_Handler 0x 36
Timer0B_Handler
NVIC_PRI5_R 0x 37
Timer1A_Handler 0x 38
Timer1B_Handler
0x C 39
Timer2A_Handler
0x000000A0 40
Timer2B_Handler
NVIC_PRI6_R
0x000000A4 41
Comp0_Handler
0x000000A8 42
Comp1_Handler
0x000000AC 43
Comp2_Handler
0x000000B0 44
SysCtl_Handler
NVIC_PRI7_R
0x000000B4 45
FlashCtl_Handler
0x000000B8 46
GPIOPortF_Handler
0x000000BC 47
GPIOPortG_Handler
0x000000C0 48
GPIOPortH_Handler
NVIC_PRI8_R
0x000000C4 49
UART2_Handler
0x000000C8 50
SSI1_Handler
0x000000CC 51
Timer3A_Handler
0x000000D0 52
Timer3B_Handler
NVIC_PRI9_R
0x000000D4 53
I2C1_Handler
0x000000D8 54
Quadrature1_Handler
0x000000DC 55
CAN0_Handler
0x000000E0 56
CAN1_Handler
NVIC_PRI10_R
0x000000E4 57
CAN2_Handler
0x000000E8 58
Ethernet_Handler
0x000000EC 59
Hibernate_Handler
0x000000F0 60
USB0_Handler
NVIC_PRI11_R
0x000000F4 61
PWM3_Handler
0x000000F8 62
uDMA_Handler
0x000000FC 63
uDMA_Error
Lab 7
Lab 8
Lab 9
77 total
INTERRUPT VECTORS

15. Timer 2A Periodic interrupt
Max is 53 sec
unsigned long TimerCount;
void Timer2_Init(unsigned long period){
unsigned long volatile delay;
SYSCTL_RCGCTIMER_R |= 0x04; // 0) activate timer2
delay = SYSCTL_RCGCTIMER_R;
TimerCount = 0;
TIMER2_CTL_R = 0x ; // 1) disable timer2A
TIMER2_CFG_R = 0x ; // 2) 32-bit mode
TIMER2_TAMR_R = 0x ; // 3) periodic mode
TIMER2_TAILR_R = period-1; // 4) reload value
TIMER2_TAPR_R = 0; // 5) clock resolution
TIMER2_ICR_R = 0x ; // 6) clear timeout flag
TIMER2_IMR_R = 0x ; // 7) arm timeout
NVIC_PRI5_R = (NVIC_PRI5_R&0x00FFFFFF)|0x ;
// 8) priority 4
NVIC_EN0_R = 1<<23; // 9) enable IRQ 23 in
TIMER2_CTL_R = 0x ; // 10) enable timer2A }
Output sound at kHz

16. Timer 2A plays sounds TATORIS Ack Output sounds here Stuff
// trigger is Timer2A Time-Out Interrupt
// set periodically TATORIS set on rollover
void Timer2A_Handler(void){
TIMER2_ICR_R = 0x ; // acknowledge
TimerCount++;
// run some background stuff here }
void Timer2A_Stop(void){
TIMER2_CTL_R &= ~0x ; // disable
void Timer2A_Start(void){
TIMER2_CTL_R |= 0x ; // enable
TATORIS
Ack
Output sounds here
Stuff
Call to stop sound
Call to start sound

17. Lab9 – Space Invaders, Pipe Dreams …
There must be at least one button and one slide pot.
There must be at least three images on the LCD display that move.
There must be sounds appropriate for the game.
The score should be displayed on the screen (but it could be displayed before or after the game action).
At least two interrupt ISRs must used in an appropriate manner.
The game must have a “time” aspect to it (For e.g., if you don’t move a sprite within a certain time it could be killed). Contrast with ConnectFour which is a taking “turns” game
The game must be both simple to learn and fun to play.

18. Lab 9 – Grading
The TA will certify your game and put you into one of two groups. Group A or B
Lab 9 will be graded subjectively by other students
During class we will setup two groups of stations each
One team member demonstrates
The other team member scores other 7 games in group
Games are rank-ordered according to level of fun. Score is based on rank in group.
80 if 0th to 49th percentile
90 if 50th to 74th percentile
100 if 75th to 100th percentile