case about nRF54L15 QSPI

[peter.min]

Hi,

1.What is the maximum rate that the QSPI of nRF54L15 can achieve?
2. Is it possible for me to use QSPI to read the flash memory while simultaneously refreshing the screen?
3. The size of my screen is 240X320X16bit LED. What is the maximum FPS it can achieve?

Best regards,

Peter.Min

[Marte Myrvold]

Hi,

1. The nRF54L15 software QSPI can run up to 64 MHz. In 4-bit mode, that is roughly 256 Mbit/s raw, which means about 32 MB/s usable data rate before protocol overhead.

2. If the flash and display are on separate interfaces, then yes. If you are using the same QSPI bus for both at the same time, it cannot be done simultaneously, as one QSPI peripheral cannot serve two masters at once.

3. With a 240x320x16-bit screen, one frame is 240 x 320 x 2 bytes = 153,600 bytes. At 64 MHz, QSPI in 4-bit mode delivers about 32 MB/s raw throughput, which would give a theoretical max FPS of 32 MB/s / 0.1536 MB/frame ≈ 208 FPS. However, the actual FPS will be lower due to flash command overhead, DMA setup, display timing, and panel/controller limits. So 60 FPS is a more common practical target. Please also note that this assumes that the screen and flash are not on the same interface.

Best regards,
Marte