SPIS maxcount

[bido1234]

im using nrf52840

with sdk 17

and segger ide

i recently discovered that the max count buffer is 16 bits meaning it has  a limit of 65k bytes. im trying to receive 100k bytes in 1 spis transaction, is there a way to achieve this or is it impossible ?

[Vidar Berg]

Hello,

The DMA pointer is limited to 16 bits like you said so you can't set up any larger buffers than that. But is there really a requirement to perform everything in such a big transaction? 100K is almost half of the available RAM on this device.

Bes regards,

Vidar

[bido1234]

Hello Vidar,

Firstly thanks for the fast response its really appreciated. Im trying to interface with a camera using spi .. the camera sends a frame every transaction. The frame is 320*320 pixels.so im trying to receive all the pixels during this transaction. 

[Vidar Berg]

Hello,

In that case, maybe you can find this example helpful: https://github.com/NordicPlayground/nrf52-ble-image-transfer-demo. It's using SPIM (not SPIS unfortunately) to get data from a camera sensor.

[bido1234]

thank you for the suggestion ill take a look at it