S130 Target Memory Modification

[Wedy Hsiao]

Hi,

Recently, I was trying to established an application based on ble_app_hrs with PCA10028.

The MCU I used is nRF51822_xxac (256KB), S130 for softdevice and the SDK is 12.3.

The original target memory setting is:

IROM1 start 0x0 size 0x40000

IRAM1 start 0x20000000 size 0x8000

Before I add my program in the project the Program Size: Code=29680 RO-data=460 RW-data=444 ZI-data=4932. -> Flash Successfully.

After I programmed my code, the size become like this: Code=42980 RO-data=1804 RW-data=940 ZI-data=7700  -> It will show as below picture

 This hex file has data in SoftDevice region.

Thus, I would like to find someone to guide me how to modified the setting to meet my requirement.

Thanks.

[Edvin]

If you started out with ble_app_hrs, then I suggest that you try to use the memory target settings that come with this example:

What you are currently seeing is that you try to program your application with the flash settings set to the entire flash of the chip, but need to save space for the softdevice in the bottom of the flash. 

The softdevice also requirre some RAM (IRAM1), so set these settings as well. The RAM requirement may change in your application, but it should be printed in the log if you need to adjust it. 

Best regards,

Edvin

[Wedy Hsiao]

May I know how do you estimate this?

[Edvin]

Wedy Hsiao said:

The size of nRF51 is 256 kB = 256 Bytes*1024= 262144 bytes =0x40000, but why you enter 0x25000 in the blank of size instead of 0x40000. 

 That is because in Keil or any other IDE that you may use, these are the settings for the applicaton. So you tell the IDE what area of the flash that is available. The softdevice uses the flash addresses: 0x00000 to 0x1AFFF, and hence, the application can use the rest: 0x1B000 to 0x40000. This means that the size of the flash available equals 0x40000-0x1B000 = 0x25000. This is the size of the flash that is available for the application. 

 

Wedy Hsiao said:

May I know where could I check the register address of memory map? And can it be tell by the target setting?

 Have you tried monitoring the log?

[Wedy Hsiao]

Hi Edvin,

I am not sure where could I find the log.

I just observed the program size after built project.

Thanks.

[Edvin]

Please see this guide on how to monitor the log:

https://devzone.nordicsemi.com/f/nordic-q-a/16979/where-can-i-see-nrf_log-output

[Wedy Hsiao]

Hi Edvin,

Recently, I also viewed the post, but still get some confused.

https://devzone.nordicsemi.com/nordic/short-range-guides/b/getting-started/posts/adjustment-of-ram-and-flash-memory

After I check the p_app_ramm_start is 0x20003EC8, does it means I should modified the IRAM1 Start from this address?

Besides, I aslo confused the description "that (IRAM1 Size + IRAM1 Start) should not be larger than the size of available RAM", I think only the start address 0x20000000 is already bigger that the chip restriction. And I also curious about that you said the space were reserve for softdevice, why it is not a stable setting as ROM? 

Thanks.

[Edvin]

Hello,

What SDK version are these screenshots from?

Were you able to monitor the log? What does your log output say?

 

Wedy Hsiao said:

Besides, I aslo confused the description "that (IRAM1 Size + IRAM1 Start) should not be larger than the size of available RAM", I think only the start address 0x20000000 is already bigger that the chip restriction

 The RAM is mapped from 0x20000000 -> the size of the RAM (0x20008000). 

The reason why it is not a stable setting like ROM is that ROM (the flash) requirement for the softdevice is a given size (the size of the binary file), while the amount of RAM that the softdevice needs depends on how many connections you support and how many services you have. In order to not take up a lot of RAM, this is set dynamically (in compile time) so that it leaves more RAM to the application if it is not needed by the softdevice. 

The reason I asked about the SDK version is that the latest screenshots doesn't match with what I see in SDK12.3.0. And are you using SES?

[Wedy Hsiao]

The screen shot is from SDK16.

I just remove the log function, the RAM is not enough to run my application.

[Edvin]

Are you using the nRF51? That isn't suited for SDK16. 

If you just unzip a new unmodified version of the SDK12.3.0, and compile the ble_app_hrs example, that should come with the correct flash and ram settings for your chip.

[Wedy Hsiao]

For SDK16 I used nRF52.

I assumed that I know how to do the size assessment. 

Thanks for your assumed that I know how to do the size assessment. 

Thanks for your guide. 

[Edvin]

So did you change the RAM assesment? What IDE do you use? Segger Embedded Studio or Keil?

[Wedy Hsiao]

Yes, I just changed the assessment, and it worked.

The IDE I used is Keil.