What are the var types of RAM data?

RE: What are the var types of RAM data?

lgs — Mon, 22 Nov 2021 16:37:33 GMT

Yes, when I try to malloc the pointer, it works. Thanks a lot.

Gaosheng Liu

RE: What are the var types of RAM data?

hmolesworth — Mon, 22 Nov 2021 16:31:47 GMT

NULL is 0x00000000 which is address 0 in Flash memory, ie not RAM. m_tx_buf can only point to RAM, so if a default initialiser has to be used it must be other than NULL. The implication is the transfer is being used without setting the m_tx_buf to a real buffer in RAM

RE: What are the var types of RAM data?

lgs — Fri, 19 Nov 2021 17:03:04 GMT

Hi Jorgen,

Thanks for the help.

One thing is that I declared the variable is not "const" type. Why is it still reporting errors?

Best,

Gaosheng

RE: What are the var types of RAM data?

Jørgen Holmefjord — Fri, 19 Nov 2021 16:41:51 GMT

Hi,

The reason for having a function to check if data is stored in RAM is that some peripherals (SPIM/TWIM/SPIS/TWIS/etc) support EasyDMA, to get/put data directly from/to RAM while CPU is sleeping. Data stored in flash can't be read using EasyDMA.

Normally, data declared as 'const' is stored in flash, while other variables/buffers are stored in RAM.

Best regards,
Jørgen