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waclawek.jan
Super User
Jan 20, 2026 4:04 PM UTC
Solved

'U5 SBus-via-DCACHE1 connectivity

Is this connection real?

waclawekjan_0-1768924913136.png

I don't think so. DCACHE implementation subchapter says:

The DCACHE1 is placed on Cortex®-M33 S-AHB bus, and caches only the external RAM
memory region (OCTOSPI, HSPI, and FMC), in the address range [0x6000 0000:0xAFFF
FFFF] of the memory map.
Indeed, by placing a bus matrix demultiplexing node in front of the DCACHE1, S-AHB bus
memory requests addressing SRAM region or peripherals region (respectively in ranges
[0x2000 0000:0x3FFF FFFF] and [0x4000 0000:0x5FFF FFFF]) are routed directly to the
main AHB bus matrix, and the DCACHE1 is bypassed.

whereas the GFXMMU slave port is at 0x2400'0000.

JW

Bubbles
BubblesBest answer
ST Employee
Jan 22, 2026 1:36 PM UTC

Hi @waclawek.jan,

well spotted. It's confirmed to be there by mistake. We'll fix this in next RM revision, probably in few weeks time.

BR,

J

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2 replies

mƎALLEm
ST Technical Moderator
Jan 20, 2026 4:15 PM UTC

Hello @waclawek.jan ,

I do agree with you. I will escalate and get back to you.

It could be a connection related to the Flash (a connection just below) not to that slave port but I need to confirm.

Internal ticket number 225541 for follow-up.

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Bubbles
BubblesBest answer
ST Employee
Jan 22, 2026 1:36 PM UTC

Hi @waclawek.jan,

well spotted. It's confirmed to be there by mistake. We'll fix this in next RM revision, probably in few weeks time.

BR,

J

To give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.