topic Re: How the GPIO pins are connected to the PLU inputs? (demo example) in LPC Microcontrollers

How the GPIO pins are connected to the PLU inputs? (demo example)

randa_zarrouk — Mon, 07 Oct 2019 10:36:57 GMT

In the demo example combination.c* it is mentioned that it is about:

a number of GPIO pins are connected to PLU inputs and the LED is used to monitor the PLU outputs to demonstrate the configuration and use of the Programmable Logic Unit (PLU) to construct a combinational logic network.

Well, the demo still not working for me. Meanwhile, I was digging into the different functions of the code.

Now I am wondering about how are the GPIO pins are connected to the PLU_IN?

The function "SetPluInputSource" (screenshot bellow) is charged of setting the PLU input source with the input value got from the GPIO, more precisely it is the function "GPIO_PinWrite" which intended to be in charge of setting this value. Meanwhile, as far as I understood, it writes the value in the pin of the GPIO not in the PLU. This makes conclude that it must be connection somewhere between the GPIO pins and the PLU pins. And I just can't find the the link (the connection) between both of them (>.<)" .

For instance, PIO1_8 is a different pin than the PLU_IN3 but according to the label of PIO1_8 which is GPIO_PLU_IN3, it shows that there it is intended that PLU_IN3 gets the value of PIO1_8.

I may missed something is the way, if not how is the PLU_IN3 going to get the value of GPIO_PLU_IN3 (PIO1_8)

Ps: the GPIO module definition :

#define DEMO_GPIO_PLU_SRC_0_PIN 8U

#define DEMO_GPIO_PLU_SRC_1_PIN 9U

#define DEMO_GPIO_PLU_SRC_2_PIN 10U

as far as I understood, those are the pin numbers to which the GPIO is routed

*: SDK_2.x 2.6.3, target board: LPCXpresso55S69

Thank you in advance.

Re: How the GPIO pins are connected to the PLU inputs? (demo example)

xiangjun_rong — Wed, 16 Oct 2019 08:54:48 GMT

Hi, Randa,

I am sorry, I confirmed with the AE team that the plu_combination example based on LPC55S69 in SDK package has issue, the AE team has notified the software team of the issue, I think they will fix it in next version.

I think you can use the plu configuration tools to generate the code for plu module based on your application. This is the link of the tools.

PLU configuration tool

Sorry for the inconvenience.

XiangJun Rong

Re: How the GPIO pins are connected to the PLU inputs? (demo example)

randa_zarrouk — Fri, 18 Oct 2019 11:15:03 GMT

Thank you very much.

Yes I am already using it. Meanwhile, it is not intuitive to make use of the PLU module. It would be helpful to have more explained examples.

In addition, while integrating the code generated by the PLU configuration tool in the overall application code in the MCUXpresso IDE, there is a small mismatch error regarding the declaration of the PLU IN in the header file LPC55S69_cm33_core0.h. I though it may be helpful to share it in a post.