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[avr-gcc-list] Warning message
From: |
Royce Pereira |
Subject: |
[avr-gcc-list] Warning message |
Date: |
Wed, 03 Oct 2007 11:43:35 +0530 |
User-agent: |
Opera Mail/9.22 (Win32) |
Hi all,
What does the following warning mean?
warning: comparison is always true due to limited range of data type
Here is the context:
I have a AVR I'm trying to connect to a DS1307 RTC chip via TWI.
To check the integrity of the DS1307 internal ram, I plan to write 4 bytes,
0x55,0xaa,0x55,0xaa in the 1st 4 loations, & read them back & verify, whenever
I power up.
My code contains this:
#define CHK_1307 0x55
uint8 twi_read(void)
{
//..........
return TWDR;
}
//-----------------------
uint8_t init_1307(void)
{
uint8_t ok = 1 ;
if(twi_read() != CHK_1307) ok= 0;
if(twi_read() != ~CHK_1307) ok= 0;
// ^^^^^^
// The offending line.
return ok;
}
//--------------------------
Thanks,
--Royce.
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- [avr-gcc-list] Warning message,
Royce Pereira <=