Custom Teensy/ESP32 PCB layout review needed

AxionQc

AxionQc

Member
I have been designing a 6 layer pcb for a Teensy/Esp32 based project and i would like to get it revised before i order the boards from JLCPCB with Epoxy Filled VIA in pad

Stackup is F.Cu, GND, In2.Cu, In3.Cu, GND, B.Cu

It uses 16MB of flash with the W25Q128JVPIM from the Teensy MicroMod

The ESP32 Pico is for Wireless and it will be programmed to the teensy with TX and RX and with EN and GPIO being connected to pin 24 and 9 respectively.

It also uses a CH221K for USB PD to get 9v 3a to 5v 4-5A with a LMR1405 running at about 2.1Mhz

I added a PSRAM pad but it uses the USON-8 footprint instead of the default SOIC/SOP

Another Major thing is that it includes a SmartMatrix based circuit to drive HUB75 Panels and APA102 with the XT30 giving power to the panels

And for IO it includes StemmaQT headers for i2c that uses 5.1k resistors.

This is for a custom All in one Protogen board that will run CoelaCant's ProtoTracer software (That was also featured in the blog not long ago), but i want to get the Teensy portion looked over,
Especially the power section and if it will start correctly, the Bootloader since its traces are long, and The Flash and crystals. I'm pretty sure the esp32's current setup will work with the teensy programing it. I think that the buck converter will work, Thermals do worry me but i think the grounds will be enough. But i am not sure about the passives since they were picked by AI by doing the math from the datasheet with the specs, I had someone look it over and they said it looks fine.

Thx for any help given

(I know i already made a post but it was not replied by anyone at all for a long time)
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Last edited:
Is it bad practice to put the VDD_SOC_IN Inductor underneath the MCU? It shortens the trace by 10-15mm

1772165145689.png



*Also i changed the TVL7573 EN/PMIC resistor to be 100K like in the schematic
 
Last edited:
Keep any inductor away from the crystal oscillator pins which can be sensitive to pickup. Normally with a BGA device the underside is peppered with lots of small decoupling caps so they can be close to the chip.
 
MarkT said:
Keep any inductor away from the crystal oscillator pins which can be sensitive to pickup. Normally with a BGA device the underside is peppered with lots of small decoupling caps so they can be close to the chip.
Click to expand...
Ah ok, also are any of the bootloader pins sensitive? I managed to move the bootloader down where the inductor was so it can have shorter traces. And does the psram and flash look like it will work?
 
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If you use W25Q128JVPIM, your hardware will be detected at MicroMod, which doesn't use a PSRAM chip.

To make PSRAM work, you will need to edit startup.c because the code as provided doesn't try to initialize the PSRAM chip. It's purely a software matter, but if you want to avoid needing to mess with the software side, best to use the same flash chip at Teensy 4.1.
 
PaulStoffregen said:
If you use W25Q128JVPIM, your hardware will be detected at MicroMod, which doesn't use a PSRAM chip.

To make PSRAM work, you will need to edit startup.c because the code as provided doesn't try to initialize the PSRAM chip. It's purely a software matter, but if you want to avoid needing to mess with the software side, best to use the same flash chip at Teensy 4.1.
Click to expand...
Im fine with tweaking stuff software side, thanks for the heads up though
 
I looked around, I'm pretty sure im not using SD_B1_05, couldnt even find it on the Schematic Symbol, and its unused in the footprint
1772432598037.png
 
Power up stuff looks basically same as Teensy 4.0.

LED D4 probably wants cathode to GND. With anode to GND, you'd need to drive it with a negative voltage to get any current to flow!
 
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