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[mAnNaRo]
Joined: 02 Dec 2005
Posts: 28
Location: Italy, Milan
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| A simple C question.... |
 Posted: Thu Feb 09, 2006 3:53 am |
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| Code: |
//--------------------------------------------------------------------------//
// Clear external EEPROM memory
//--------------------------------------------------------------------------//
void clear_MEMORY(void) {
int32 mem_address;
for (mem_address = 0; mem_address <= 0xFFFF; mem_address++) {
write_ext_eeprom(mem_address, 0x00);
}
}
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How can I save RAM memory using an int16 for mem_address counter instead of int32? With int16 the compiler tell me that the condition is always TRUE (that's true). When I increment an int16 variable 0xFFFF I get a rollover to zero?
Thanx
Alex |
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Roebi
Joined: 12 Jan 2006
Posts: 6
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| The Solution-Code |
| Posted: Thu Feb 09, 2006 4:28 am |
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What about this:
| Code: | void clear_MEMORY(void) {
int16 mem_address = 0;
do {
write_ext_eeprom(mem_address, 0);
mem_address++;
} while (mem_address);
} // clear_MEMORY
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Best regards
Roebi |
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jds-pic
Joined: 17 Sep 2003
Posts: 205
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| Re: The Solution-Code |
| Posted: Thu Feb 09, 2006 10:57 am |
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| Roebi wrote: | What about this:
| Code: | void clear_MEMORY(void) {
int16 mem_address = 0;
do {
write_ext_eeprom(mem_address, 0);
mem_address++;
} while (mem_address);
} // clear_MEMORY
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since you are doing bytewise writing to the eeprom, you can save yourself a lot of time clearing the memory by doing a read first, and only writing a zero if the read value is nonzero. for even a small eeprom this will probably cut lots of "long" 10ms writes out of the picture.
| Code: | void clear_MEMORY(void) {
int16 mem_address = 0;
do {
if !(read_ext_eeprom(mem_address)) {
write_ext_eeprom(mem_address, 0);
mem_address++;
}
} while (mem_address);
} // clear_MEMORY
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