How to assign bit values at once to different port pins of different I/O ports?

how to assign bit values at once to different port pins of different I/O port through a register which I define as comprised of those port pins of I/O ports?

I want to define a variable(name=my_reg) of uint8_t type which i plan to use it as a register of 8 bits. Each bit of this register should send its value to different bits of different I/O ports.

For example When my_reg = 3;

LATAbits.LATA0 which is my_reg.0 should be 1
LATAbits.LATA1 which is my_reg.1 should be 1
LATCbits.LATC0 which is my_reg.2 should be 0
LATCbits.LATC4 which is my_reg.3 should be 0
LATBbits.LATB5 which is my_reg.4 should be 0
LATBbits.LATB0 which is my_reg.5 should be 0
LATAbits.LATA7 which is my_reg.6 should be 0
LATAbits.LATA6 which is my_reg.7 should be 0

I am new to C. I defined a struct which is comprised of 8 subplaces all is 1 bit. But i couldn't give a value to MY_REG.

Try this but not tested.

That example only works if the bits are in the same port. The 'MY_REG' in post #1 used bits across three different ports.

Brian.

baileychic said:

Try this but not tested.

Code:

#define myPortA LATA

typedef struct {
uint8_t B0:1;
uint8_t B1:1;
uint8_t B2:1;
uint8_t B3:1;
uint8_t B4:1;
uint8_t B5:1;
uint8_t B6:1;
uint8_t B7:1;
} BitField;

BitField myPortB;

Code:

myPortA.B0 = 1;
myPortA.B0 = 0;

Click to expand...

thanks for reply. i tried something similar but it didn't work. I dream something like that; when i give a value to myPortB, myBportB would distribute/place all its bit values to appropriate port pins.

This results an error of main.c:49:13: error: incompatible types when assigning to type 'myPortB' from type 'int'

The processor can only write to one port at a time. Why do you want to hide this fact from the programmer?
There is no generic way to do this, but for a few ports with the registers at contiguouos addresses, it could be possible to place a larger data type at the lowest address.
I will not give an example, because I think it is a terrible idea.

std_match said:

The processor can only write to one port at a time.

Click to expand...

I don't aim a parallel work. I have microchips explorer16/32 development board. And 8 LED's on that board are driven from different ports. (4 of them are from PORTA, 3 from PORTB and one is from PORTC) As i sad in my first post i try to send an ON-OFF command to all those LEDs at once. But after replies to my question i understand that it is a rather difficult task may be impossible. Thanks.

I suggest that you do it with a function. Call it set_leds(uint8_t led_bits) or similar. The function can easily extract the bits for each output port.

I haven't tried different ways to see which is quickest/smallest but my first approach would be a function like this:

It might be worth trying 'LATAbits.LATA0 = (led_bits & 0x01)?1:0;' on the basis that any '1' should be 'true' regardless of actual bit value.

It's worth noting the doing the checks bit-by-bit in a function can only change the state of one bit at a time. If done using bit shifts and then ANDing & ORing the bits it is possible to set/reset more than one bit simultaneously but only within one port at a time.

Brian.