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Topic: Solutions to this audio amplifier design task
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Joined: Apr 25, 2017
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Hi!

I am building home automation hifi audio preamplifier, which consists of motherboard and arbitrary number of audio zones.

Every zone is represented with PCB volume controller board (volume control IC with stereo audio input and audio output).

Now, the end user will be able to upgrade/downgrade this pre-amp with adding/removing audio zones (minimal 1 zone - classic stereo, maximum 8 zones - true zone preamp).

When the power is on, the motherboard with main microcontroller (Microchip PIC32MX795F512L datasheet: http://www.kynix.com/uploadfiles/pdf8798/PIC32MX795F512L-80I2fPT.pdf) will have to figure out the configuration of preamp, i.e., figure out the number of zone pcbs, inserted into motherboard.

Here are some details of PIC32MX795F512L:

Voltage-Supply-Vcc-Vdd: 2.3 V ~ 3.6 V
Core-Size: 32-Bit
Program-Memory-Size: 512KB (512K x 8)
Data-Converters: A/D 16x10b
Oscillator-Type: Internal
Supply-Voltage-Max: 3.6 V
Supply-Voltage-Min: 2.3 V
Maximum-Operating-Temperature: + 85 C
Minimum-Operating-Temperature: - 40 C
Operating-Supply-Voltage: 2.3 V to 3.6 V


Can anyone tell me the possible solutions for this task? Thanks very much!
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Joined: Mar 28, 2005
Posts: 13,100
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One of the most reliable ways is to use 4 I/O spots and short out pins for each one to identify a location where a card is inserted.

Short pins: 1, 2, 3, 4, 1&2, 1&3, 1&4, 2&3, 2&4, 3&4, 1&2&3, 1&2&4, 1&3&4, 1&2&3&4

That gives you up to 14 configurations from 4 I/O locations with a common ground.

It would potentially not require the slots to be loaded sequentially as well, but let logic dictate which slots are loaded.

I'm not sure if this is for a class project or for something else as there are a fair number of multi-source, multi-zone preamps on the market already.

I personally use the Crestron Bipad8 in all of my designs which is a fixed setup 16 source to 8 rooms preamplifier, with cascading capability to add up to three total units for up to 24 rooms.

These are available on the used market for around 100 bucks. So, any type of project to repeat this level of effort needs to be extremely price appropriate.

No, it isn't card based (Bipad8) and needs a separate control system and programming, but it's extremely flexible to those who can do both.
AV Integrated - Theater, whole house audio, and technology consultation during the build and installation process in the Washington, DC metropolitan area.