atmega32 avr c programming code

[boukamoha]

hi every one
can some one tell me the difference between setting the portB of ATMEGA32 as PORTB=0b11111110; and PORTB &=(1<<PB0) and PORTB &=0b11111110
best regards

 

[roland_vs]

---

Code C - [expand]
1
2
3
4
5
6
7
8
9
10
11
12
13
14
PORTB = 0b11111110;      // assigning a value to PORTB unconditionally
 
PORTB &=0b11111110;      // reading PORTB and MASKING OUT the LSB bit ONLY
PORTB = PORTB & 0xFE;      // same statement written differently
 
PORTB &= (1<<PB0);      // isn't correct if it should be the same as the previous statement
// it reads as PORTB = PORTB & 0x01 (1<<PB0) is (1<<0) or bit shift (0) positions(s)...
 
PORTB &= ~(1<<PB0);      // if you want the same effect as the previous statement
 
// so to set a bit
PORTB |= (1<<PB0);
// to clear a bit
PORTB &= ~(1<<PB0);

---

 

[boukamoha]

thx was helpful