esp32 spi 64kBytes transaction and dma question

brebisson
Posts: 12
Joined: Fri Dec 22, 2023 9:44 am

esp32 spi 64kBytes transaction and dma question

Postby brebisson » Wed Oct 30, 2024 3:06 pm

Hello,

I am using a TTGO board with a LCD, no PSRAM, and I want to use the SPI to send a full LCD frame (64KBytes) to the LCD.

I am using the spi API described here:
https://docs.espressif.com/projects/esp ... on-example

The data is 64KB frame buffer which is a global variable (in DRAM I assume as there is nothing else on this chip).

Can I create a single transaction to send these 64KB at once?
Will it use the DMA to send the data (the spi_bus_initialize call did specify SPI_DMA_CH_AUTO).

Thanks,
Cyrille

ESP_Sprite
Posts: 9692
Joined: Thu Nov 26, 2015 4:08 am

Re: esp32 spi 64kBytes transaction and dma question

Postby ESP_Sprite » Thu Oct 31, 2024 12:02 am

Yes you can and yes it will. Just make sure to set max_transfer_sz in your spi bus config accordingly.

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