topic Re: LPC4357 CLKOUT in LPC Microcontrollers

LPC4357 CLKOUT

skysky — Wed, 08 Mar 2017 10:01:01 GMT

LPC4357 clock out pin(CLKOUT) is unable to output the CLK.(i can not check a wave on pin P1_19)

i configure such as follow:

LPC_SCU->SFSP1_19 = (1 << 5) | 4;
LPC_CGU->BASE_OUT_CLK = (1 << 11) | (0 << 24);

So，Is there a lack of configuration?

Re: LPC4357 CLKOUT

jeremyzhou — Thu, 09 Mar 2017 02:02:31 GMT

Hi Sky,

In the LPCOpen library demo, you can use the following code to set up the clock via the CLK0 pin.

Chip_SCU_ClockPinMuxSet(0,(SCU_MODE_FUNC1|SCU_MODE_INACT));
/* Setup base clock for CLKOUT */
Chip_Clock_SetBaseClock(CLK_BASE_OUT, CLKIN_CRYSTAL, false, false);‍‍‍‍‍‍

LPCOpen library:

LPCOpen Software for LPC43XX|NXP
Have a great day,
Ping

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Re: LPC4357 CLKOUT

skysky — Thu, 09 Mar 2017 03:22:00 GMT

hi jeremyzhou:

now i have another problem about extern singal frequence measure.

Because the singal(Sin Wave/Pwm) frequence is too big(about 70+MHz),i think about using

the timer in MOTORCONPWM peripheral。

and i use the way of External event counting (Counter mode),the pin MCI0 is used to input the Signal to be measured。

then set a match value in counter mode,then play the role of frequency division,(100 prescaler-Check the MOTORCONPWM's output pin MCOA0)。

In order to test whether this method is effective，i use CLK0(IDVE clock)clock connect to MCI0。

So,i find a error:

1.CLK0 be set to 2MHZ,the MIC counter is correct,the MCOA0 output 20KHZ

2.CLK0 be set to 4MHZ,the MIC counter is corrent,the MCOA0 output 40KHZ

3.CLK0 be set to 8MHZ,the MIC counter is error,the MCOA0 output also about 40KHZ

So ,my question is the counter frequence of MCPWM's counter mode is 8MHZ?

refer to the other peripheral ie.TIMER capture mode,check a external singal's rising edge need 2 PCLK,the max frequence is bigger than 8MHZ.

my code such follow:

LPC_CCU1->CLK_APB1_MOTOCONPWM_CFG = 0x7;

LPC_RGU->RESET_CTRL1 = 1 << 6; //MOTOCONPWM_RST
while(!(LPC_RGU->RESET_ACTIVE_STATUS1 & (1 << 6)));

LPC_SCU->SFSP8_2 = ((1 << 4) | (1<<6) | (1<<7) | 3);//   MIC0
LPC_SCU->SFSP9_3 = 1;      //MCOA0
LPC_SCU->SFSP9_4 = 1;   //MCOB0

LPC_MCPWM->CON_CLR = 0xffffffff;
LPC_MCPWM->CNTCON_SET = (1 << 29) | 1; //channel0 counter / rising

LPC_MCPWM->LIM0 = 100;      //100 prescaler
LPC_MCPWM->MAT0 = 50;

thank you very much

Re: LPC4357 CLKOUT

jeremyzhou — Thu, 09 Mar 2017 06:57:10 GMT

Hi sky,

I'd highly recommend you to crate a new thread for the another question, and sharing the link of the thread.

Thanks for your understanding and cooperation.
Have a great day,
Ping

Re: LPC4357 CLKOUT

skysky — Fri, 10 Mar 2017 09:57:18 GMT

thank you your advise

i am sorry to trouble you