Well, I use the union for ease of saving config bits to an E2PROM,
saving those bits as whole bytes (chars).

Francisco


Gerhard Fiedler wrote:

>>I use this in HiTech C
>>
>>typedef struct Port_s
>>{
>>    unsigned    bit0    :1;
>>    unsigned    bit1    :1;
>>    unsigned    bit2    :1;
>>    unsigned    bit3    :1;
>>    unsigned    bit4    :1;
>>    unsigned    bit5    :1;
>>    unsigned    bit6    :1;
>>    unsigned    bit7    :1;
>>} Port_t;
>>
>>union
>>{   unsigned char   Byte;
>>    Port_t          Bits; }     PortA, PortB, PortC;
>>
>>and use it like this
>>
>>if (!PortB.Bits.bit5)
>>    PortA.Byte = 0xAA;
>>
>>
>
>I use something similar on occasion, but usually not for the ports. What is
>the advantage of this union/bitfield over the Hi-Tech standard header
>declarations, like
>
>  if( !RB5) PORTA = 0xaa;
>
>?
>
>(Of course I usually wouldn't use RB5 in such a context, but rather a
>meaningful name that gets associated with RB5 in a header file. But the
>question remains the same.)
>
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>.
>
>
>

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