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DaHu_285096
Level 5
Level 5
10 likes received 250 replies posted 100 replies posted

I wired up P4.0 to analog input and found the 4200 only allows ADC on Port 2 (0..7) and thought I'd ask the question before re-laying up my PCB.

Is there any way to use a comparator or voltage monitor on this pin? I do not need the actual voltage but I need to generate a signal when battery falls below a certain value. (Like the LVD interrupt but I need it on the battery and not the micro supply voltage).

Thanks

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1 Solution
Anonymous
Not applicable

Hi,

Port 4 (and higher ports) have restrictions because of absence of port adapter. Technical reference manual section 7.10 talks about it -

http://www.cypress.com/file/126171/download

SAR ADC can connect to Port 0 to Port 3. In the case of Port 2, it uses only SARMUX bus whereas in the case of other port pins, AMUX bus is also used, in addition, for routing.

If you wish to use ADC, I would suggest Port 2 pins and for comparator, dedicated pins P0[0]/P0[1] or P0[2]/P0[3].

- Rajiv

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2 Replies
Anonymous
Not applicable

Hi,

Port 4 (and higher ports) have restrictions because of absence of port adapter. Technical reference manual section 7.10 talks about it -

http://www.cypress.com/file/126171/download

SAR ADC can connect to Port 0 to Port 3. In the case of Port 2, it uses only SARMUX bus whereas in the case of other port pins, AMUX bus is also used, in addition, for routing.

If you wish to use ADC, I would suggest Port 2 pins and for comparator, dedicated pins P0[0]/P0[1] or P0[2]/P0[3].

- Rajiv

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Thanks Rajiv, I'll lay re-lay the PCB to use P2.7 as Analog input

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