Baskaran
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pi400-audio output Schematic

Thu Sep 22, 2022 12:20 pm

Developing Carrier Board using Pi400
I need to implement Audio Input Connector ,
Could you advice which is Audio Signal Pin from the 40 Pin on pi400
Share Pi400 Module to Audio output signal Design
Thanks
K.B

[moderator changed input to output]

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FTrevorGowen
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Re: pi400-audio Input Schematic

Thu Sep 22, 2022 2:12 pm

Baskaran wrote:
Thu Sep 22, 2022 12:20 pm
Developing Carrier Board using Pi400
I need to implement Audio Input Connector ,
Could you advice which is Audio Signal Pin from the 40 Pin on pi400
Share Pi400 Module to Audio Input signal Design
Thanks
K.B
Could you clarify where the "Audio Input Connector" and "Audio Siganl Pin" are expected to be (ie. on the P400 or elsewhere) - AIUI a Pi only has audio output (via the TRRS connector** or HDMI) . IIRC a P400 only via HDMI (unless there are "unpopulated" pads/connections on the board - there's no connector on the P400 I'm posting from and, AFAIK no GPIO pin can easily provide "audio" w/o extra circuitry.)
Trev.
** http://www.cpmspectrepi.uk/raspberry_pi ... deo_Cables
Still running Raspbian Jessie or Stretch on some older Pi's (an A, B1, 2xB2, B+, P2B, 3xP0, P0W, 2xP3A+, P3B, B+, and a A+) but Buster on the P3B+, P4B's & P400. See: https://www.cpmspectrepi.uk/raspberry_pi/raspiidx.htm

Baskaran
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Re: pi400-audio Input Schematic

Fri Sep 23, 2022 5:02 am

Thanks for the Answer

Pls refer my attached Schematic ,i want to implement in the Same in my carrier Board

In my Carrier Board i want to Connect "vu Level Meter Module"" through Audio Jack
Attachments
Audio Jack.png
Audio Jack.png (49.4 KiB) Viewed 379 times

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davidcoton
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Re: pi400-audio Input Schematic

Fri Sep 23, 2022 7:40 am

Baskaran wrote:
Fri Sep 23, 2022 5:02 am
...
In my Carrier Board i want to Connect "vu Level Meter Module"" through Audio Jack
So you want an audio output (from the Pi), not an input (into the Pi)?

If so, the Pi4 circuit is suitable, AFAIK -- along with setting up the necessary driver.
You will have to re-assign the output to a pair of pins on the GPIO -- the standard signals are not routed to the GPIO (and probably do not exist on the Pi400).
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rpdom
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Re: pi400-audio Input Schematic

Fri Sep 23, 2022 8:38 am

You can use any of the PWM GPIOs 12 or 18 and 13 or 19. You then use the audremap dtoverlay to direct the audio output to those pins

Code: Select all

dtoverlay=audremap,pins_12_13
using the default pins, or

Code: Select all

dtoverlay=audremap,pins_18_19
for the alternate pins.

Also, if you haven't found out already, part number of U5 is NC7WZ16P6X
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Baskaran
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Re: pi400-audio Input Schematic

Mon Sep 26, 2022 7:42 am

Thank you for the Answer
I want to use 3.5mm Audio Jack ,What is the Part number recommended part number for the Audio Jack on carrier Board ?

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rpdom
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Re: pi400-audio Input Schematic

Mon Sep 26, 2022 9:13 am

I don't know the recommended part for the jack socket, but for audio only you could use pretty much any 3.5mm stereo jack socket, connect the 0V/gnd to the sleeve connection and leave out the VDAC_COMP connection and D4 as they won't be needed.
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mahjongg
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Re: pi400-audio Input Schematic

Mon Sep 26, 2022 1:54 pm

In my humble opinions, most early RPI's use a PC21348 Farnell order code 2579730 or a reichelt order code CLIFF FT6320, but yes, you can use any jack plug connector you like. It doesn't have to be a version for a AV connector.

Adafruit has information on how to direct the PWM audio signal to a GPIO pin of your choice, it uses the same audio filer/driver circuit picture in its blog post about how to do this for a Zero (which doesn't have audio out). The picture shows the ring isn't connected to GND, and the connector is for a TRRS plug, which might nor be correct, so IMHO this schematic isn't correct for the plugs I recommend, which are for TRS connectors, with switches in them, but look at their datasheet. and just connect the sleeve to GND, the ringt to the right audio channel, and the tip to the Left (or mono) channel.

I don't get why they (the RPF) didn't add audio out on the RPI 400, except for not having place for this bog-standard audio connector they normally choose, they could have used a dimensionally smaller one. They don't need a plug with switches or a TRRS (with two rings) connector. except when they also want to output Video (AV out).

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