topic Re: Configure pin as open drain in LPCXpresso IDE

Configure pin as open drain

lpcware — Thu, 16 Jun 2016 01:52:12 GMT

Content originally posted in LPCWare by vinylrider on Tue Nov 10 09:39:35 MST 2015
Hello everyone,

i want to configure P1.27 and P1.28 ( lpc1769 ) as an open drain pins. I have externally used an 4,1kohm resistor as a pull up tied up to 3.3Volts. The problem is that after executing the following code in my multimeter i get always 0volts in both pins but it should be Vdd and GND respectively.
I cannot understand what is my fault! ??? I had configured these two pins as follows.

        LPC_PINCON->PINSEL3 &= ~(0b11<<22);
LPC_PINCON->PINSEL3 &= ~(0b11<<24);

LPC_GPIO1->FIODIR |= 1<<27;
LPC_GPIO1->FIODIR |= 1<<28;


LPC_PINCON->PINMODE_OD1 |= 1<<27;   //open drain
LPC_PINCON->PINMODE_OD1 |= 1<<28;//open drain


LPC_GPIO1->FIOPIN1 |= 1<<27;
LPC_GPIO1->FIOPIN1 &= ~(1<<28);

thank you very much for any help!

Re: Configure pin as open drain

lpcware — Thu, 16 Jun 2016 01:52:13 GMT

Content originally posted in LPCWare by R2D2 on Tue Nov 10 10:00:06 MST 2015

Quote: vinylrider

LPC_PINCON->PINSEL3 &= ~([color=#f00]11[/color]<<22);
LPC_PINCON->PINSEL3 &= ~([color=#f00]11[/color]<<24);

What's that :quest:

Re: Configure pin as open drain

lpcware — Thu, 16 Jun 2016 01:52:13 GMT

Content originally posted in LPCWare by vinylrider on Tue Nov 10 10:15:31 MST 2015
sorry i meant

LPC_PINCON->PINSEL3 &= ~(0b11<<22);
LPC_PINCON->PINSEL3 &= ~(0b11<<24);

Re: Configure pin as open drain

lpcware — Thu, 16 Jun 2016 01:52:14 GMT

Content originally posted in LPCWare by R2D2 on Tue Nov 10 10:41:38 MST 2015

Quote: vinylrider
LPC_GPIO[color=#f00]1[/color]->FIOPIN[color=#f00]1[/color] |= 1<<27;

And what's that :quest:

Re: Configure pin as open drain

lpcware — Thu, 16 Jun 2016 01:52:14 GMT

Content originally posted in LPCWare by vinylrider on Tue Nov 10 10:56:03 MST 2015

Quote: R2D2

Quote: vinylrider
LPC_GPIO[color=#f00]1[/color]->FIOPIN[color=#f00]1[/color] |= 1<<27;

And what's that :quest:

That is MY FAULT...THANK YOU !!!

it should be:

LPC_GPIO1->FIOPIN |= 1<<27;

i tested it and now it works just fine as it should!