8051 game project

Isn't the IP register addressable with an 8 bit number?

Isn't the IP register addressable with an 8 bit number?

PsySc0rpi0n

If you meant the IR register, yes it's 8 bit.

Isn't the IP register addressable with an 8 bit number?

PsySc0rpi0n

If you meant the IR register, yes it's 8 bit.

ExperimenterUK

I was talking about the interrupts priority register. Is it only bit addressable or 8 bit only?

The INTERRUPT PRIORITY (IP) register is bit addressable.

You can set one bit or write 8 bits at once.

Ok, thanks.

Another question:

Can the value at timer x be readed and stored into a variable? Meaning after starting T1 (TR1 = 0x01), for instance, read the value that is at T1 at a given moment?

Just for knowledge: any SFR register in 8051 whos address is divisible by 8 is bit addressable
Yes You can read timer registers at any time.

Could you help me on how to do that? Is it just:

unsigned char time;
time = T1;

or

unsigned char time;

time = THx;

or

 
unsigned char time

time =TLx;

One more question...

I'm trying to generate a sequence of 4 random numbers using srand (time (NULL)); and rand () % 4; but for some reason the generated numbers are always 2 and 3.

I think I can't use fopen, fread, fclose and FILE * in SDCC, can I?

If you want to read the complete timer register then best is this way:

unsigned int time; /* TH and TL combined makes a 16-bit value */

time = TH1; /* for timer 1 */
time = (time << 8) | TL1; /* makes it a 16-bit value */

I'm trying to generate a sequence of 4 random numbers using srand (time (NULL)); and rand () % 4; but for some reason the generated numbers are always 2 and 3.

PsySc0rpi0n

srand is not very efficient as I know. why are you doing a mod with 4?

I think I can't use fopen, fread, fclose and FILE * in SDCC, can I?

PsySc0rpi0n

You can but you need a storage media (like SD card or something) and Filesystem driver (FAT32/FAT16 etc.). These functions are not built into sdcc. you need external library.. check this out: http://www.8051projects.net/mmc-sd-interface-fat16/

If you want to read the complete timer register then best is this way:

unsigned int time; /* TH and TL combined makes a 16-bit value */

time = TH1; /* for timer 1 */
time = (time << 8) | TL1; /* makes it a 16-bit value */

I'm trying to generate a sequence of 4 random numbers using srand (time (NULL)); and rand () % 4; but for some reason the generated numbers are always 2 and 3.

PsySc0rpi0n

srand is not very efficient as I know. why are you doing a mod with 4?

I think I can't use fopen, fread, fclose and FILE * in SDCC, can I?

PsySc0rpi0n

You can but you need a storage media (like SD card or something) and Filesystem driver (FAT32/FAT16 etc.). These functions are not built into sdcc. you need external library.. check this out: http://www.8051projects.net/mmc-sd-interface-fat16/

ajay_bhargav

Ok, I'll try that way to read timer.

About the other question, alternatively to reading timers or using srand (time(NULL)) to generate random numbers, I was also thinking about to read '/dev/urandom' or even using 'clock()' inside srand () to get a better seed but I think SDCC doesn't recognise clock () or fread, fopen, fclose and FILE*.

Edited;
I'm using

% 4

to generate 4 numbers between 0 and 3, and according to the generated number, I'll launch the mine in 1of the 4 corners of the LCD.

Meaning that I want to randomize the LCD address where the mines will be launched!