Battery RAM

 Battery RAM

Controller : LPC2368(ARM 7)

Issue : Battery RAM values not storing . Junk values getting stored on it.

Hi People ,

I am using LPC2368 (ARM7) . I am facing the following issue with the
Battery backup RAM .

My Pclk for Battery backup RAM is Pclk = Cclk / 4 ;

And I am storing data as shown below

#define BATTERY_RAM_BASE_ADDRESS 0xE0084000

/* ALLOCATION */

#define BSR_Data1 (*(volatile unsigned
long*)(BATTERY_RAM_BASE_ADDRESS 0x000))
#define BSR_Data2 (*(volatile unsigned long
*)(BATTERY_RAM_BASE_ADDRESS + 0x004))
#define BSR_Data3 (*(volatile unsigned long
*)(BATTERY_RAM_BASE_ADDRESS + 0x008))

As Static Battery RAM can be accessed only word-wise(32bit only)

Note : The Battery RAM is a 2 kbyte static RAM residing on the APB bus.
The address range is
0xE008 4000 to 0xE008 47FF. The SRAM can be accessed word-wise (32-bit)
only.

And I store it as ,

Unsigned int Store_Data;

Store_Data = BSR_Data1 ;

And Reading it as

BSR_Data1 = Store_Data ;

Is this the Correct way ?

Because after a day all the data that I store is getting erased.

Thanks in advance, Pls help me out guys on this issue.

Regards,
Samjith Wasim . A

 all the data that I store is getting erased

How are you sure that the data was correctly stored in the first place?

 RE: all the data that I store is getting erased

How are you sure that the data was correctly stored in the first place?

Reply

Unsigned int Store_Data;
Store_Data = BSR_Data1 ;

And Reading it as
BSR_Data1 = Store_Data ;

By doing this I can read/write the first data alone correct ?

for consecutive data I will use like this

Store_next_data = BSR_Data2;

And read it as
BSR_Data2 = Store_next_data;

is this the correct method ??

 RE: all the data that I store is getting erased

Is this the correct way of pointing data to Battery RAM .

How do I write/read a complete structure of each 32 bit data on to the Battery RAM ?

Regards,
Samjith Wasim . A

Thanks in advance

 RE: all the data that I store is getting erased

How to check whether variables stored in first place ??

The method of storing/reading my word-wise data is this correct ?

 RE: all the data that I store is getting erased

Guys can you Please help me on this issue as soon as possible.

Regards,
Samjith

 RE: all the data that I store is getting erased

If BSR_Data1 is a variable in the battery-backed memory, then this is a write, and not a read:

And Reading it as

BSR_Data1 = Store_Data ;

To test if the memory works, you should write a significant amount of data - together with a checksum, CRC or similar, and then power off the unit and wait for a while. Then power up and read out the values - the checksum should still be correct.

Have you remembered to connect the VBAT signal to a battery or super-cap?

 you do not give the specifics and ..

since you do not state clock speed or type if BBRAM, is the write/read timing slow enough to satisfy the requirements of the BBRAM?

This has come up before in other contexts.

Erik

 RE: you do not give the specifics and ..

Note that the NXP LPC2368 has internal 2kB battery-backed RAM (if external power is applied to the dedicated supply pin)

 Don't miss the obvious

Have you checked the voltage of the battery?

 RE: Don't miss the obvious

Guys Thanks a ton ,

I just checked by Bat Voltage and found to be drained ..

I will come back after checking it with in a day or two.

Regards,
Samjith