| ??? 02/26/09 10:22 Read: times |
#162877 - Yes, but... Responding to: ???'s previous message |
David Prentice said:
You normally want to use binary constants for things like setting a particular bit in a special function register. So you may:
#define LED_RED 3 #define LED_GREEN 0 #define LED_BLUE 1 variable = (1<<LED_RED) | (1<<LED_GREEN) | (1<<LED_BLUE); // RGB lit variable = (1<<LED_RED) | (0<<LED_GREEN) | (1<<LED_BLUE); // R_B lit Agreed, but that always looks really cumbersome & ugly to me. I would tend, rather, to do something like: // Bit positions - 0 is LSB #define LED_RED_BIT_NUM 3 #define LED_GREEN_BIT_NUM 0 #define LED_BLUE_BIT_NUM 1 // Bit values #define LED_RED_BIT (1<<LED_RED_BIT_NUM) #define LED_GREEN_BIT (1<<LED_GREEN_BIT_NUM) #define LED_BLUE_BIT (1<<LED_BLUE_BIT_NUM) variable = LED_RED_BIT | LED_GREEN_BIT | LED_BLUE_BIT; // RGB lit variable = LED_RED_BIT | LED_BLUE_BIT; // R_B lit Just my preference, of course! For this specific case, of course, you could make definitions like LED_RED_ON and LED_BLUE_OFF... |
| Topic | Author | Date |
| Bin in C | 01/01/70 00:00 | |
| Possible solution | 01/01/70 00:00 | |
| You need to check if this works with your compiler | 01/01/70 00:00 | |
| Does it work with any? | 01/01/70 00:00 | |
| popular demand | 01/01/70 00:00 | |
| My compiler is IAR | 01/01/70 00:00 | |
| because that's a non-standard (non-ANSI) extension | 01/01/70 00:00 | |
| What made you beleive that it would work? | 01/01/70 00:00 | |
| Use #define names | 01/01/70 00:00 | |
| Yes, but... | 01/01/70 00:00 | |
| Use macros for that. | 01/01/70 00:00 | |
| facilitates my understanding | 01/01/70 00:00 | |
| Working with flags | 01/01/70 00:00 | |
| how I do it | 01/01/70 00:00 | |
I use a macro | 01/01/70 00:00 |