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pikman
Joined: 20 Dec 2004
Posts: 4
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| Driver for linear access of 8 memory 24LC512 512KB!! |
 Posted: Sun Jan 07, 2007 10:17 pm |
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Hello, this simple driver allows to address 8 serial eeproms 24LC512 as one chip of 512KB (524.288 bytes), in my develop it has been of a lot of help, I hope also helps. 
Ariel.
| Code: |
///////////////////////////////////////////////////////////////////////////////////
//// Library for lineal address to a bank of 8 24LC512 chip memory ////
//// ////
//// 0 to 0x07FFF ////
//// //// ////
//// init_24512x8(); Call before the other functions are used ////
//// ////
//// writeByte24512x8(a,d); Write the byte (int8)d to the address (int32)a ////
//// ////
//// d=ReadByte24512x8(a); Read the byte int8)d from the address (int32)a ////
//// ////
//// ////
///////////////////////////////////////////////////////////////////////////////////
#ifndef EEPROM_SDA
#define EEPROM_SDA PIN_B1
#define EEPROM_SCL PIN_B0
#endif
#use i2c(master, sda=EEPROM_SDA, scl=EEPROM_SCL)
#define MULTIPLE_EEPROM_ADDRESS int32
#define EEPROM_SIZE 524288
void init_ext_eeprom()
{
output_float(EEPROM_SCL);
output_float(EEPROM_SDA);
}
void writeByte_24512x8(int32 memaddress, int8 data){
int16 address;
int8 controlbyte;
short int status;
address=memaddress;
controlbyte=(0xa0 | ((make8(memaddress,2))<<1));
i2c_start();
i2c_write(controlbyte);
i2c_write(address>>8);
i2c_write(address);
i2c_write(data);
i2c_stop();
// AckNolege pooling
i2c_start();
status=i2c_write(controlbyte);
while(status==1)
{
i2c_start();
status=i2c_write(controlbyte);
}
i2c_stop();
}
int8 readByte_24512x8(int32 memaddress){
int16 address;
int8 controlbyte;
int8 data;
address=memaddress;
controlbyte=(0xa0 | ((make8(memaddress,2))<<1));
i2c_start();
i2c_write(controlbyte);
i2c_write(address>>8);
i2c_write(address);
i2c_start();
i2c_write(controlbyte|1);
data=i2c_read(0);
i2c_stop();
return data;
}
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Last edited by pikman on Sun Jan 07, 2007 10:23 pm; edited 2 times in total |
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BOB_SANTANA
Joined: 16 Oct 2006
Posts: 110
Location: HOVE, EAST SUSSEX
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| Posted: Mon Jan 08, 2007 3:34 pm |
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Excellent Work Pikman
Could you be kind enough just to do a quick example program
Thanks in advance
_________________
BOB_Santana  |
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last_turk
Joined: 13 Sep 2006
Posts: 3
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| 64K x 8 (512 Kbit) |
| Posted: Tue Mar 20, 2007 9:28 am |
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24AA512/24LC512/24FC512 (24XX512*) is a 64K x 8 (512 Kbit)
and eeprom address must be 0 to 0xFFFF
thanks for all |
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pikman
Joined: 20 Dec 2004
Posts: 4
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| Posted: Mon Apr 02, 2007 11:23 pm |
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| last_turk, I don't understant, my driver is to use whit 8 units 24AA512/24LC512/24FC512, is right you point there are 64KB (512 Kbit), but every one, 64kb x 8 = 512Kb ( or best 524288 bytes ), then adress you must enter is 0 to 0x07FFF, and not 0 to 0xFFFF as you say, when you use this driver of course. |
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treitmey
Joined: 23 Jan 2004
Posts: 1094
Location: Appleton,WI USA
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| Posted: Tue Apr 03, 2007 8:07 am |
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According to spec sheet section 5.1 there are 19 bits of address A0->A15 and
chip select bit A0,A1,A2.
I wrote a simular driver for a FRAM FM24C256
http://www.ccsinfo.com/forum/viewtopic.php?t=24099
But in my driver I use a multi-read to speed things up. And in that
multi read my driver can go accross chip boundries.
Have you thought about that?
Here is your spec sheet.
http://ww1.microchip.com/downloads/en/DeviceDoc/21754G.pdf
see page 8 5.1 Contiguous Addressing Across Multiple Devices
and page 9 6.2 Page Write ((what i call multiwrite)) up to 127 more writes.
and 8.3 Sequential Read. |
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