Using P12[4] and P12[5]

[NiVa_4337911]

Hi,

I have some issues using P12[4] and P12[5] in a custom board with CY8C5888AXI-LP096. When the pin P12[4] is used as digital o/p, there is a plm.m0038 warning, but I am not using I2C[0], so how can I disable the warning?

An LED connected to P12[5] (pin5) is also not working when the P12[4] is connected with an internal signal, but the LED is working fine if I assigned the signal to some other pins instead of P12[4]. Is this because of I2C[0 module with the pin-out in P12[4] and P12[5], if yes how can I disable this module and its outputs?

[Len_CONSULTRON]

NiVa,

Are you will to share your project with the forum?

At least share the TopDesign.  We can review your pin assignments for proper parameter selection that might be causing your difficulty.

Len

[Ekta_N]

Hello NiVa_4337911​

If possible, could you please attach the schematic of the custom board for us to review and the screenshot of the warning that you are getting?

Could you also share the configurations made for both the pins in the Top Design ?

I tried assigning the P12[4] and P12[5] pins as digital output but did not get any warning.

Please ensure that you are following the guidelines given in PSoC 3 and PSoC 5LP Hardware Design Consideration guide: https://www.cypress.com/documentation/application-notes/an61290-psoc-3-and-psoc-5lp-hardware-design-...​while designing the custom board.

Best Regards

Ekta

[NiVa_4337911]

Hi,

Thanks for the replied, sorry, it was not a warning but a note. I attached an example project, I didn't get time to test this project to drive the LED connected at PIN 5, but shows the message "The pin named TP3(0) at location P12[4] prevents usage of special purposes: I2C:SCL".

[Ekta_N · Accepted solution]

Hi,

The message that you are getting is just a note suggesting that using the pin 12[4]  for TP3 digital output will block it from being used as I2C: SCL Pin. This is because the pins 12[5] and 12[4] are special purpose input output pins and these pins when used as I2C SDA and I2C SCL lines provide wake from sleep on an address match functionality. Any I/O pin can be used for I2C SCL or I2S SDA if wake from sleep is not required.

Since you are using an I2C component in your design which are using different pins, on build creator is providing this note suggesting "The pin named TP3(0) at location P12[4] prevents usage of special purposes: I2C:SCL"

Disabling the I2C component from the top design will cause the note to go away.

Can you assign a GPIO pin to the LED and see if the issue still occurs?

Best Regards

Ekta

[Len_CONSULTRON]

NiVa,

As Ekta explained, the note is just informing you that using the pins P12[5] and P12[4] for a different purpose is not "illegal" and will not cause a proper project build. 

The PSoC5 is very highly routable.  In other words, the internal configuration you create in the TopDesign can be assigned almost to any pin on the PSoC.   Certain pins on the PSoC have "preferred" paths to internal resources such as Opamps, comparators, SPI, I2C, UART and others.  The "preferred" assignments to certain pins allow for the highest frequency input or output in the case of the digital resources and the lowest series resistance in the case of the analog resources.

The note is just to inform you that your assignment may not be optimal for speed or certain performance.

Len