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JohnyMielony / ESP32TLCDCEmu

CD changer emulator for Tuner List (Update List) Renault radio
GNU General Public License v3.0
8 stars 2 forks source link

Questions about some connections in the schematics #3

Open ggovdeli opened 2 years ago

ggovdeli commented 2 years ago

Hello JohnyMielony,

I stumbled upon your project and was keen on building a PCB that contained an ESP32-WROOM and a buck converter to power it. However, I'm not able to figure out the pinouts especially with J1 and J2 connectors (I have an Update-List radio, pinout sourced from http://tlcdcemu.sourceforge.net/hardware.html). I also couldn't quite figure out why capacitors C1 to C4 are included, and why the Q1 and Q2 MOSFETs are used.

Can you enlighten me about these? Are you able to share a PCB diagram and/or values of the components? Thanks in advance.

JohnyMielony commented 2 years ago

JP1 is for putting ESP32 into programming mode. JP2 is connected on other end to radio. Pins 1 - 6 are connected to radio's: 1 - ground, 2 - HU ON, 3 - 12V, 4 - TX, 5 - SPDIF IN, 6 - RX. It can be easily read from schematic. Capacitors are rather obvious. They are for power filtering, preventing noise and brownouts. MOSFETs are for level shifting, which is also obvious. You're not that into electronics, right? Values are on schematic. You just need to calculate resistor (R3, R4) values for SPDIF voltage divider. Remember that ESP32 operates on 3,3V not 5V, so You calculate it right. I have a PCB design made in Eagle, if it's right for You I can share.

ggovdeli commented 2 years ago

Hello JohnyMielony,

Thanks for your swift and very thorough response.

I'm currently an EEE sophomore, so I got quite confused because I'm learning all about these just about now.

I'll get my hands on the components and build a prototype. I'll probably keep this issue posted as I learn about PCB design, then might request the PCB designs of yours so I can dissect and examine them like your schematic. Thanks for your time.

worthis commented 3 months ago

JP1 is for putting ESP32 into programming mode. JP2 is connected on other end to radio. Pins 1 - 6 are connected to radio's: 1 - ground, 2 - HU ON, 3 - 12V, 4 - TX, 5 - SPDIF IN, 6 - RX. It can be easily read from schematic. Capacitors are rather obvious. They are for power filtering, preventing noise and brownouts. MOSFETs are for level shifting, which is also obvious. You're not that into electronics, right? Values are on schematic. You just need to calculate resistor (R3, R4) values for SPDIF voltage divider. Remember that ESP32 operates on 3,3V not 5V, so You calculate it right. I have a PCB design made in Eagle, if it's right for You I can share.

Hello JohnyMielony, What types of Q1 and Q2 were used? It is not indicated in the schematic. What is the point of recalculating the resistors R3 and R4 nominals? Can each head unit have different voltages on pin 5 of the JP2 connector?

JohnyMielony commented 2 months ago

@worthis it is for You to choose. Any logic level mosfets with diode that can handle that voltage will do fine. There is practically no significant current there. As I stated before, they're just for level shifting.

R3 R4 depend on what voltage operates your uC. I don't remember which values I used, bu You can find it easily on web. It is just very basic electronic knowledge.