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PSoC 4 MCU

Contributor

Hello,

   

I am currently trying to use 12 pins as analog inputs of a PSOC 4 BLE pioneer board and I am not very sure this is possible. I am only able to route 6 Analog pins using the port P3[0-5], since the P3[6-7] are used for an RGB on the pioneer board. I will need 6 more pins and I was trying to use some Analog MUXs in order to accomplish this and I was also trying to use P2[0-5] for this. The problem is I am not able to route the analog pins. Basically I was wiring the external pins to input of a analog mux and the output of it to one input of the SAR ADC but this error always appear: Net "\ADC:muxout_plus\" is connected to analog mux "AMuxSeq_1" and analog mux "\ADC:cy_psoc4_sarmux_8\_CYAMUXSIDE_A", but it may connect to only one analog mux when it is an analog mux common connection.

   

As a information from PSOC: An analog mux common connection may not be connected to another analog mux. We expect to remove this limitation in a future release. To work around this limitation, try cloning or buffering the common signal.

   

So my question for the more experimented people here: Is there a way to use 12 analog pins and if yes where I can find more information? Also if someone know how to clone or buffering the common signal I will appreaciate the information.

   

 

   

Thanks a lot!

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1 Solution
Esteemed Contributor II

Try it the way like in the attached project.

   

The EOS (End Of Sampling) interrupt should be used to switch the AMUX to the next channel

   

 

   

Bob

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4 Replies
Esteemed Contributor II

Try it the way like in the attached project.

   

The EOS (End Of Sampling) interrupt should be used to switch the AMUX to the next channel

   

 

   

Bob

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Contributor

Hello Bob,

   

Thanks for your answer but the example you gave me did not help me a lot. I will explain here what I need and also attached a modified project maybe you can have a look at what I want to achieve.

   

I have some sensors that uses 2 ADC channel/sensor therefore I need to convert one pair of signals at once. I have 6 sensors and therefore I will need an ADC SAR with 6 inputs in order to convert 3 sensors outputs at a time. I put 6 MUXs with 2 inputs and link the sensors in such a way that 3 will be converted once, then I will switch the MUXs to second input, convert them again and so one.

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Esteemed Contributor II

As you already experienced, your schematic will not work. This is due to the internal routing capabilities. You an use my suggestion from the last archive I posed. This will convert all 12 input channels. When the cycle is completed you can pick the required sensor values for the current state and ignore the other .

   

 

   

Bob

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Contributor

Hello Bob,

   

I think this is the only option in order to have more than 6 pins converted. This is not very nice since the 4200 BLE series should be able to use 16 channels but on the pioneer I can only use 6, because some pins are link to the RGB LED and some are not exposed on board. On top of this the routing rules limit this even further. It would be great if this can change in the future. You should not be limited if you are not using the OP amps of the chip but maybe this will be changed.

   

Thanks a lot!

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