Open-drain for alternate function LPC17XX

[xvidaurrazaga]

Hi everyone

I am trying to set pins SCK0 and MOSI0(BRIDGE 1) in open-drain mode for microntroller 1752 but setting the register LPC_PINCON->PINMODE_OD1 to open drain does not seem to work. 

Clock Pin: P1[20]/MCI0/PWM1[2]/SCK0

Data Pin: P1[24]/MCI2/PWM1[5]/MOSI0

LPC_PINCON->PINMODE_OD1 |= 1<<20; //Bit P1.20 is open drain
LPC_PINCON->PINMODE_OD1 |= 1<<24; //Bit P1.24 is open drain

If I configure the pin as GPIO the pin is set in open-drain. 

If there any way to set a non-GPIO pin in open-drain mode?

Thank you. 

[nxf77486 · Accepted solution]

Hello,

The GPIO  pins are only configurable in pull-up/down resistors, open drain mode, and repeater mode. The I2C is a dedicated open-drain pins without pull-up/down.

The open drain SPI option is not implemented in this design LPC17xx.

 In conclusion the GPIO can only be set in open-drain mode.

[xvidaurrazaga]

thank you so much for your reply