I need to use cJSON to parse the uart data. I found the file in SDK15.3 but how can I use the related function?
I need to use cJSON to parse the uart data. I found the file in SDK15.3 but how can I use the related function?
Hi,
just add sources and headers to your project and call functions as usual... you also need to add mem_manager library from SDK. cJSON has a good README with detailed instructions how to use this library.
Is there a routine example of how to use the memory management library?
Yes, there is no problem when parsing JSON data. But when I create JSON data, I will use cJSON_CreateNumber. So after I blocked all the other parts related to JSON parsing, I called cJSON_CreateNumber and found that as long as the total number of memory blocks from XXS to XXL exceeds 255, calling cJSON_CreateNumber will cause the program to die in HardFault_Handler. There is no log information (I didn't open men_manger module log)
Whether to use malloc is not the key, the key is that when I call nrf_mem_init, and the total number of memory blocks from XXS to XXL exceeds 255, calling cJSON_CreateNumber will cause the program to die in HardFault_Handler.
The IDE I am using is SES and KEIL, and I don't know how to display debug traces (disassembly, stack, registers) where hard faults occur. The end result is just the program stuck in HardFault_Handler
I tried to set XXS and XXL to 500 and 300, everything is fine.. I can suppose that you have block sizes not ailgned to 4 (some instructions require word-aligned operands).
I don't know how to display debug traces (disassembly, stack, registers) where hard faults occur.
Keil debugger shows everything if you run program under debug session.
The memory block size needs to be a multiple of 4?
The memory block size needs to be a multiple of 4?
Standard malloc always allocates a word-aligned block. nrf_malloc will allocate a new block starting from next byte, so if your block size is not word-aligned, allocations will be unaligned too.
Byte alignment of memory! ! ! I know this concept until now. It’s true that the memory block size is set to a multiple of 4 and the problem disappears.
So, my understanding is that the byte alignment principle is followed when using malloc or nrf_malloc, and the memory address is aligned in 4 bytes. Is my understanding correct?
when using malloc
nrf_malloc, and the memory address is aligned in 4 bytes
You mean block size? Yes, in both cases you'll get a word-aligned address.
all right. I got it. Thanks Dmitry!!! I will continue my project.
