Ehrm... maybe you are right... also about I2C and I2S...Is this related to your post here: https://forums.raspberrypi.com/viewtopi ... 3#p2313390 ?
If so you don't need a PCIe switch as you're only intending to connect a single PCIe device.
See my reply: https://forums.raspberrypi.com/viewtopi ... 3#p2313543
I think my Audio HAt need both to be able to work correctly...
I still haven't received the Pi 5, the post office should have shipped it Friday but got delayed.
So I can't begin testing
I thought I would still need to figure out the exact specs of these Pi52 hats,
and there is no Datasheet to read...
There are boards that works at full gen3 speed but this Switch does not allows that...
This is an important part of the equation.
If the screen uses another port and the Audio DAC works correctly,
maybe just a single SSD HAt is the right solution...
You seem to be thinking that Pi addons/HATs work and connect the same way as they do on x86 PC hardware. They do not.
On x86 everything is PCie. On Pi almost nothing is. Almost everything connects via the 40 pin GPIO header.
If your stated addons (NVMe, I2S DAC HAT, DSI screen) all require a PCIe connection you will need a PCIe switch. If they connect a via standard x86 type PCIe edge connectors you'lll need adapters too.
If, as I strongly suspect the only PCIe device is the NVMe drive not only do you not need the switch but it will actively prevent use at (the uncertified) gen 3 speeds. It will also add latency.
If you're worried about pin conflicts between the officiual M.2 HAT and other HATs, I suggest you use an alternative, third party board (like this one*) that does not connect to the GPIO header at all.
I2C is by design a multi drop bus. Each device on it (except, IIRC, the master) has a unique address. As long as no two devices on the same bus have the same address everything will be fine.**
MIPI/DSI is not PCIe either. The Pi 5 has two connectors (the FFC ones to between the ethernet jack and micro HDMI jacks) that are dedicated to DSI/CSI. That doesn't mean you can plug in an arbitary screen and expect it to work though - you may need device tree config and drivers for it. Touch may require further connections to the GPIO header (and drivers) too but as you've not told us make and model of the screen we can only guess.
As has been said already, the best place to get information on those PCIe switch HATs is the manufacturer.
Same applies to your DAC and screen.
For info on the Pi's GPIO header and the pin usage of many HATs start at https://pinout.xyz/ and see also the official documentation.
*: It's what I use. Not least because it can take physically longer drives than the official HAT can.
**: Unles one or more devices use 5V IO. That can damage the Pi.
Unless the NVDAC in question is using a Pcie for the M.2 drive and the GPIO for the Audio DAC...
I got all the info before getting the pcm5102a that used GPIO and it was probably broken.
I tested it with a Pi Pico and the signal clock was 48Khz, 3V, 20ms slew edge... I checked every single component pin by pin
and desoldered a couple smd arrays to be 100% certain these weren't faulty. Resoldered. move over.
I got no audio out. only the Pico Pwm worked. Same thing on the Rasp Pi 5.
I probably had done everything right but the DAC was faulty.
There is zero troubleshooting for all these new DAC online.
I downloaded Piscope and checked all GPIO activity.
Now for the Pcie protocol... this must vary on a board basis...
And I cannot find the relevant documentation of how the system decides to assign the resources,
if there's a plug and play involved for the Pcie and SSD, or I have to add manual config as I have with GPIO
devices.
Ok. Need to get breakfast and gong, long day ahead.
Pimoroni is very low on stock and could find the model I wanted anywhere....
I need audio...
The raspi 5 has no audio jack....
Statistics: Posted by Zool64Pi — Wed May 07, 2025 6:23 am