topic Re: lpc 4337 Phase-shift PWM in LPC Microcontrollers

lpc 4337 Phase-shift PWM

vianneyfenart — Thu, 18 Jul 2019 21:11:41 GMT

hi,

Is it possible to do a phase shift pwm with SCT of lpc 4337 mcu?

thanks

Re: lpc 4337 Phase-shift PWM

xiangjun_rong — Fri, 19 Jul 2019 10:51:36 GMT

Hi, Viuanney,

Can you refer to the ticket in the community which talks about the phase-shift feature of PWM signals.

https://community.nxp.com/message/765201?commentID=765201#comment-765201

Hope it can help you

Xiangjun Rong

Re: lpc 4337 Phase-shift PWM

vianneyfenart — Sat, 20 Jul 2019 14:55:40 GMT

Hi, xiangjun.rong,

thanks for your reply.

i read the post.

if i understand for doing a shift i need to put the first OUPUT PWM to an INPUT PIN for second OUTPUT PWM?

i need to shift 10 output pwm....

best regards

Re: lpc 4337 Phase-shift PWM

xiangjun_rong — Tue, 23 Jul 2019 07:01:59 GMT

Hi, Vianney,

I think the user code for the PWM shift is too complicated, you can use a simple way to implement it.

Can you clarify your required PWM shift signal timing? do you need complementary PWM signal with deadtime?

Xiangjun Rong

Re: lpc 4337 Phase-shift PWM

vianneyfenart — Tue, 23 Jul 2019 17:31:21 GMT

Hi, xiangjun.rong,

In fact i only need to shift each pwm signal of few milliseconds....i don't need complementary pwm with deadtime.

actually i use 10 SCT pinout and all signal are synchronous....

can you help me please?

best regards

Re: lpc 4337 Phase-shift PWM

xiangjun_rong — Wed, 24 Jul 2019 07:32:56 GMT

Hi, Vianney,

I have developed a simple code to implement the phase shift for two PWM signal based on LPC54114, I attach the code, but you have to modify it based on the LPC4337, for example AHBCLKCTRL register for enabling gated clock and pin assignment.

Hope it can help you

XiangJun Rong

//The SCT0_OUT1 can output PWM signal with 50 duty cycle from PIO0_8 pin
//The SCT_OUT2 can output PWM signal with 50 duty cycle fron PIO0_9 pin
//The SCT0_OUT1 and SCT0_OUT2 PWM signal has 90 degree phase shift.

void SCT0_PWM(void)
{
   SYSCON->AHBCLKCTRL[1]|=(1<<2); //SET SCT0 bit
   SCT0->CONFIG = (1 << 0) | (1 << 17); // unified 32-bit timer, auto limit
   SCT0->SCTMATCHREL[0] = SystemCoreClock/100; // match 0 @ 100 Hz = 10 msec
   SCT0->EVENT[0].STATE = 0xFFFFFFFF; // event 0 happens in all states

   //set event1
   SCT0->SCTMATCHREL[1]=0x00;
   SCT0->EVENT[1].STATE = 0xFFFFFFFF; // event 1 happens in all states
   SCT0->EVENT[1].CTRL = (1 << 12)|(1<<0); // match 1 condition only

   //set event2
   SCT0->SCTMATCHREL[2]=(SystemCoreClock/100)/2;
   SCT0->EVENT[2].STATE = 0xFFFFFFFF; // event 2 happens in all states
   SCT0->EVENT[2].CTRL = (1 << 12)|(2<<0); // match 2 condition only

   //set event3
   SCT0->SCTMATCHREL[3]=(SystemCoreClock/100)/4;
   SCT0->EVENT[3].STATE = 0xFFFFFFFF; // event 3 happens in all states
   SCT0->EVENT[3].CTRL = (1 << 12)|(3<<0); // match 3 condition only

   //set event4
   SCT0->SCTMATCHREL[4]=3*(SystemCoreClock/100)/4;
   SCT0->EVENT[4].STATE = 0xFFFFFFFF; // event 4 happens in all states
   SCT0->EVENT[4].CTRL = (1 << 12)|(4<<0); // match 4 condition only

   //PWM output1 signal
   SCT0->OUT[1].SET = (1 << 1); // event 1 will set SCT1_OUT0
   SCT0->OUT[1].CLR = (1 << 2); // event 2 will clear SCT1_OUT0
   SCT0->RES |= (3 << 2); // output 0 toggles on conflict

   //PWM output2 signal
   SCT0->OUT[2].SET = (1 << 3); // event 3 will set SCT1_OUT0
   SCT0->OUT[2].CLR = (1 << 4); // event 4 will clear SCT1_OUT0
    SCT0->RES = (3 << 4); // output 0 toggles on conflict

//PWM start
SCT0->CTRL &= ~(1 << 2); // unhalt by clearing bit 2 of the CTRL
}

Re: lpc 4337 Phase-shift PWM

xiangjun_rong — Wed, 24 Jul 2019 09:19:41 GMT

Hi, Vianney,

Pls refer to the doc, hope it can help you

XiangJun Rong

https://community.nxp.com/docs/DOC-343979

Re: lpc 4337 Phase-shift PWM

vianneyfenart — Wed, 24 Jul 2019 17:39:41 GMT

Hi XiangJun Rong,

Thank you for you help : i will test the code with my cpu !

Best regards