readUserBackupRegister

[Pete]

Hello everyone –

Does anyone have example code that they can share showing the use of read and write user backup register? I can’t get it to work right.

                    if ((ret = dot->writeUserBackupRegister(0, sleeptime)) != mDot::MDOT_OK){ 
                            pc.printf("Failed to write sleeptime\r\n"); 
                        } else {
                            pc.printf("Wrote sleeptime\r\n"); 
                        }

I’m trying to save my sleep time of dot->sleep(sleep_time, mDot::RTC_ALARM); between sleeps.

Thanks for any advice. I know C++ only enough to be dangerous.

[Pete]

Anyone?

This is an mDot, that I’m trying to keep persistent variables across sleep.

[Jason Reiss]

What is not working?

sleeptime != sleep_time

[Pete]

I’m sorry, I was not very clear, and had typos. Both readUserBackRegister and write fail.

Beginning code:

    if ((ret = dot->readUserBackupRegister(0, sleeptime)) != mDot::MDOT_OK){ 
        pc.printf("Failed to read - sleeptime is %d\r\n",sleeptime); 
        } else {
            pc.printf("Read in sleeptime as %d\r\n",sleeptime); 
        }
    if(sleeptime > 2000) sleeptime = 1; // sleeptime is some crazy number
    pc.printf("Sleep set for %d Minutes\n\r", sleeptime);  
     

End Code

            
            if ((ret = dot->writeUserBackupRegister(0, sleeptime)) != mDot::MDOT_OK){ 
                    pc.printf("Failed to write sleeptime\r\n"); 
                    } else {
                          pc.printf("Wrote sleeptime as %d\r\n",sleeptime); 
                    }
                

Output is

Failed to read - sleeptime is 134219489
Sleep set for 1 Minutes
.
.
.
Failed to write sleeptime
Sleeping 60 seconds or 1 minutes.

• This reply was modified 7 years, 3 months ago by Pete.

[Pete]

Are there no Multitech devs around there that help a guy out?

[Jason Reiss]

I think it is working although your check fails because it is expecting MDOT_OK to be returned.

MDOT_OK is defined as 0 and is equivalent to false.
The check is printing failed if 0 is NOT returned.
In the success case true will be returned which is definitely not 0.

From mDot.h the backup register functions are declared to return a true or false value
https://os.mbed.com/teams/MultiTech/code/libmDot-mbed5/file/mDot.h/

bool writeUserBackupRegister(uint32_t reg, uint32_t data);
bool readUserBackupRegister(uint32_t reg, uint32_t& data);

• This reply was modified 7 years, 3 months ago by Jason Reiss.

[Pete]

Thanks for looking at my code snippets, Jason –

I have other code that uses the same format and works fine, so I don’t think it has to do with my check on MDOT_OK. I did change my test to:

if ((ret = dot->readUserBackupRegister(0, sleeptime)) == true)

But no difference.

The problem is that it successfully reads and writes, but the actual data is no good.

When waking from sleep, I get –
Read in sleeptime as 134219489

Even though I have written the register to be 1, it still reads as 134219489.

Register 1 is no better, it’s just a 0, and I cannot change it.

[Jason Reiss]

Can you compile and try this example on your mDot?

https://os.mbed.com/users/jreiss/code/BackupRegisterExample/

[Pete]

Hi Jason –

Thanks so much for the example code!

Your code works perfectly for me. With this, I now have a good example, and can work to fix my code.

I really appreciate you taking the time to help this amateur out!

[Jason Reiss]

Glad to help Pete.
If you ever need more timely support, our support portal is also available to customers. support.multitech.com

[Author]

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