I have purchased this board - [wiki=https://store.sure-electronics.com/product/AA-AB32256]%[/wiki] - from Sure Electronics. It is based on the TAS5754 and is attractive in that it has an I2S input.
It also has an I2C input which I mistakenly thought led directly to the I2C port on the TAS5754. As I wanted to control the amplifier - and in particular - the volume from a microcontroller, this seemed ideal. However, the board I2C terminal leads to a microcontroller embedded on the board. Sure Electronics sells a volume control for it, but to have more general control possibilities I need to be able to generate the I2C signals myself. These seem to be a state secret.
My first question is: does anybody know where I can find out how this particular I2C port works (e.g. The I2Cs address, what data needs to be sent etc.)?
I have asked the manufacturer. They seem to imply that I can change the volume by adjusting the voltage levels. I’m assuming that this is the power supply (e.g. high volume = powered at 19V, low volume = powered at, say, 5v). I could then use a variable voltage regulator (suitably rated) and adjust the voltage (0 volume) using a digitally controlled potentiometer.
Is this a technique that could work? Are there any gotchas that I should know about?
Many thanks for any hints.
It also has an I2C input which I mistakenly thought led directly to the I2C port on the TAS5754. As I wanted to control the amplifier - and in particular - the volume from a microcontroller, this seemed ideal. However, the board I2C terminal leads to a microcontroller embedded on the board. Sure Electronics sells a volume control for it, but to have more general control possibilities I need to be able to generate the I2C signals myself. These seem to be a state secret.
My first question is: does anybody know where I can find out how this particular I2C port works (e.g. The I2Cs address, what data needs to be sent etc.)?
I have asked the manufacturer. They seem to imply that I can change the volume by adjusting the voltage levels. I’m assuming that this is the power supply (e.g. high volume = powered at 19V, low volume = powered at, say, 5v). I could then use a variable voltage regulator (suitably rated) and adjust the voltage (0 volume) using a digitally controlled potentiometer.
Is this a technique that could work? Are there any gotchas that I should know about?
Many thanks for any hints.
You can change the volume by writing 0-255 (-103.5-24dB) to register 61 and 62.
However, I dont know if you can just put another master on the bus besides the onboard micro. The micro probably also handles state control (power on sequencing, writing settings register), so cutting it of would probably not work unless you implement this full code on your external micro.
However, I dont know if you can just put another master on the bus besides the onboard micro. The micro probably also handles state control (power on sequencing, writing settings register), so cutting it of would probably not work unless you implement this full code on your external micro.
Thanks for the quick response. This was what I thought I could do. However, the onboard micro seems to completely hide the chip’s I2C port (probably to ensure the correct operation of the state setting operations you mention). And I can't find any info on how to control the onboard micro.