NRF52810-QFAA-R datasheet(49/483 Pages) NORDIC

49 / 483 page

Core components

• Write no more than 6 bytes back to the writerBuffer located in RAM at address 0x20000005.

The memory layout of these buffers is illustrated in EasyDMA memory layout on page 49.

readerBuffer[0]

readerBuffer[1]

readerBuffer[2]

readerBuffer[3]

readerBuffer[4]

writerBuffer[0]

writerBuffer[1]

writerBuffer[2]

writerBuffer[3]

writerBuffer[4]

writerBuffer[5]

0x20000000

0x20000004

0x20000008

Figure 5: EasyDMA memory layout

The WRITER.MAXCNT register should not be specified larger than the actual size of the buffer

(writerBuffer). Otherwise, the channel would overflow the writerBuffer.

Once an EasyDMA transfer is completed, the AMOUNT register can be read by the CPU to see how many

bytes were transferred. For example, CPU can read MYPERIPHERAL->WRITER.AMOUNT register to see how

many bytes WRITER wrote to RAM.

4.6.1 EasyDMA array list

EasyDMA is able to operate in a mode called array list.

The array list does not provide a mechanism to explicitly specify where the next item in the list is located.

Instead, it assumes that the list is organized as a linear array where items are located one after the other

in RAM.

The EasyDMA array list can be implemented by using the data structure ArrayList_type as illustrated in the

code example below:

#define BUFFER_SIZE 4

typedef struct ArrayList

{

uint8_t buffer[BUFFER_SIZE];

} ArrayList_type;

ArrayList_type ReaderList[3];

READER.MAXCNT = BUFFER_SIZE;

READER.PTR = &ReaderList;

The data structure only includes a buffer with size equal to the size of READER.MAXCNT register. EasyDMA

uses the READER.MAXCNT register to determine when the buffer is full.

4430_161 v1.0

NRF52810-QFAA-R Datasheet(PDF) 49 Page - Nordic Semiconductor