Check System frequency of Nucleo F411RE board. Also F401RE.

Dependencies:   mbed

<May 12th, 2015>
I have confirmed that both mbed lib. and mbed-src lib. have updated to change F411RE mbed System clock and USB clock as below.

fVCO = fPLL-in x (PLLN/PLLM), fPLL-out = fVCO/PLLP, fUSB-out = fVCO/PLLQ
Use PLL with PLLN=192, PLLM=4
Use HSE(not Xtal but External Clock)=8000000Hz
PLL/Base   freq= 384000000Hz
Use PLL with PLLP=4, PLLQ=8
PLL/System freq=  96000000Hz
PLL/USB    freq=  48000000Hz

SYSCLK clock freq. =  96000000Hz
HCLK   clock freq. =  96000000Hz
PCLK1  clock freq. =  48000000Hz
PCLK2  clock freq. =  96000000Hz


mbed lib. Rev. -> 98 & mbed-src lib. Rev. ->539
We can use USB with proper colok!.

If you would like to use 100MHz System clock, please refer updated "Nucleo_F411RE_SysClk".
--------

I made a clock checking program for Nucleo F411RE and F401 mbed board.
Picture shows F411RE example.
/media/uploads/kenjiArai/f411_clk.png
System frequency is 100MHz. Looks okay for me.
USB frequency is 44.4MHz? -> USB clock needs accurate frequency 48MHz.
Once keeping 100MHz system clock freq., we can select PLLQ value only 9 or 8.
If PLLQ=9, USB Freq. is 44.4MHz (current setting).
If PLLQ=8, USB Freq. is 50.0MHz.

Best selection looks follows.
PLL clock -> HSE = 8MHz
PLLN= 192, PLLM = 4
PLL Freq. = (PLL Clock)*(PLLN/PLLM) = 8MHz * 192 / 4 = 384MHz
System clock = (PLL Freq.)/PLLP = 384MHz/4 = 96MHz
USB clock = (PLL Freq.)/PLLQ = 384MHz/8 = 48MHz

Is this result okay?
or
Is my program wrong?

main.cpp

Committer:
kenjiArai
Date:
2015-05-12
Revision:
2:e530159dd7aa
Parent:
1:2d6d2ccd87f8

File content as of revision 2:e530159dd7aa:

/*
 * mbed Application program / Frequency Counter with GPS 1PPS Compensation
 *
 * Copyright (c) 2014 Kenji Arai / JH1PJL
 *  http://www.page.sannet.ne.jp/kenjia/index.html
 *  http://mbed.org/users/kenjiArai/
 *      Created: Nobember   2nd, 2014
 *      Revised: Nobember   2nd, 2014
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
 * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE
 * AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
 * DAMAGES OR OTHER  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
#if defined(TARGET_NUCLEO_F401RE) || defined(TARGET_NUCLEO_F411RE)

#include "mbed.h"

//  Object ----------------------------------------------------------------------------------------
Serial pc(USBTX, USBRX);
DigitalOut myled(LED1);

//  Definition ------------------------------------------------------------------------------------
#define BAUD(x)                 pc.baud(x)
#define GETC(x)                 pc.getc(x)
#define PUTC(x)                 pc.putc(x)
#define PRINTF(...)             pc.printf(__VA_ARGS__)
#define READABLE(x)             pc.readable(x)

// USB Frequency
#define USB_FREQ_H          48100000
#define USB_FREQ_L          47900000

//  RAM -------------------------------------------------------------------------------------------

//  ROM / Constant data ---------------------------------------------------------------------------
char *const cmsg1 = "freq=";
char *const cmsg2 = "Use HSI(internal RC/High speed)";
char *const cmsg3 = "Use HSE(External Xtal)";
char *const cmsg4 = "Use PLL with";
char *const cmsg5 = "??? following infromation is not valid !";
char *const cmsg6 = "clock freq. =";
char *const cmsg7 = "No clock";
char *const cmsg8 = "Use LSE(external Xtal)=32768Hz";
char *const cmsg9 = "Use LSI(internal RC/Low speed), RC=";
char *const cmsg10= "Use HSE(external Xtal & prescaler)";

//  Function prototypes ---------------------------------------------------------------------------

//  Function prototypes ---------------------------------------------------------------------------

//-------------------------------------------------------------------------------------------------
//  Control Program
//-------------------------------------------------------------------------------------------------
void put_rn ( void )
{
    PUTC('\r');
    PUTC('\n');
}

void cpu_freq(void)
{
    uint32_t m1 = 0, m2 = 0, m3 = 0, m4 = 0, m5 = 0;

    PRINTF("--- Power Control ---");
    put_rn();
    m1 = PWR->CR;
    PRINTF( "CR       = 0x%08x", m1 );
    put_rn();
    m1 = PWR->CSR;
    PRINTF( "CSR      = 0x%08x", m1 );
    put_rn();
    PRINTF("--- Clocks related Reg. ---");
    put_rn();
    m1 = RCC->CR;
    PRINTF( "CR       = 0x%08x", m1 );
    put_rn();
    m1 = RCC->PLLCFGR;
    PRINTF( "PLLCFGR  = 0x%08x", m1 );
    put_rn();
    m1 = RCC->CFGR;
    PRINTF( "CFGR     = 0x%08x", m1 );
    put_rn();
    m1 = RCC->CIR;
    PRINTF( "CIR      = 0x%08x", m1 );
    put_rn();
    m1 = RCC->AHB1RSTR;
    PRINTF( "AHB1RSTR = 0x%08x", m1 );
    put_rn();
    m1 = RCC->APB2RSTR;
    PRINTF( "APB2RSTR = 0x%08x", m1 );
    put_rn();
    m1 = RCC->APB1RSTR;
    PRINTF( "APB1RSTR = 0x%08x", m1 );
    put_rn();
    m1 = RCC->AHB1ENR;
    PRINTF( "AHB1ENR  = 0x%08x", m1 );
    put_rn();
    m1 = RCC->APB2ENR;
    PRINTF( "APB2ENR  = 0x%08x", m1 );
    put_rn();
    m1 = RCC->APB2LPENR;
    PRINTF( "APB2LPENR= 0x%08x", m1 );
    put_rn();
    m1 = RCC->APB1LPENR;
    PRINTF( "APB1LPENR= 0x%08x", m1 );
    put_rn();
    m1 = RCC->CSR;
    PRINTF( "CSR      = 0x%08x", m1 );
    put_rn();
    put_rn();
    m1 = RCC->CFGR & RCC_CFGR_SWS;  /* Get SYSCLK source */
    switch (m1) {
        case 0x00:  // HSI used as system clock
            PRINTF( "%s, %s%dHz", cmsg2, cmsg1,HSI_VALUE );
            m2 = HSI_VALUE;
            break;
        case 0x04:  // HSE used as system clock
            PRINTF( "%s, %s%dHz", cmsg3, cmsg1, HSE_VALUE );
            m2 = HSE_VALUE;
            break;
        case 0x08:  // PLL used as system clock
            PRINTF("fVCO = fPLL-in x (PLLN/PLLM), fPLL-out = fVCO/PLLP, fUSB-out = fVCO/PLLQ");
            put_rn();
            m5 = (RCC->PLLCFGR >> 6) & 0x1ff;   // PLLN
            m1 = RCC->PLLCFGR & 0x3f;           // PLLM
            PRINTF( "%s PLLN=%d, PLLM=%d", cmsg4, m5, m1 );
            put_rn();
            m3 = (RCC->PLLCFGR >> 22) & 0x1;    // Clock source
            if (m3 == 0) {
                // HSI oscillator clock selected as PLL clock source
                m2 = (HSI_VALUE * (m5 / m1));
                PRINTF( "%s, RC=%dHz", cmsg2, HSI_VALUE );
            } else {
                // HSE selected
                m2 = (((HSE_VALUE) * m5) / m1);
                if ((RCC->CR >> 18) & 0x01) {  // check HSEBYP bit
                    // HSE(not Xtal) selected as PLL clock source
                    PRINTF( "Use HSE(not Xtal but External Clock)=%dHz", HSE_VALUE );
                } else {
                    // HSE(Xtal) selected as PLL clock source
                    PRINTF( "%s, Xtal=%dHz", cmsg3, HSE_VALUE );
                }
            }
            put_rn();
            PRINTF("PLL/Base   %s%10dHz", cmsg1, m2);
            put_rn();
            m3 = (RCC->PLLCFGR >> 16) & 0x03;  // PLLP
            switch (m3) {
                case 0:
                    m3 = 2;
                    break;
                case 1:
                    m3 = 4;
                    break;
                case 2:
                    m3 = 6;
                    break;
                case 3:
                    m3 = 8;
                    break;
            }
            m4 = (RCC->PLLCFGR >> 24) & 0x0f;  // PLLQ
            PRINTF("%s PLLP=%d, PLLQ=%d", cmsg4, m3, m4);
            put_rn();
            PRINTF("PLL/System %s%10dHz", cmsg1, m2/m3);
            put_rn();
            PRINTF("PLL/USB    %s%10dHz", cmsg1, m2/m4);
            m2 = m2/m4;
            if ((m2 > USB_FREQ_H) || (m2 <USB_FREQ_L)){
                PRINTF(" -> USB Freq. is out of range!");
            }
            put_rn();
            break;
        default:    // Not come here
            PRINTF( cmsg5 );
            break;
    }
    put_rn();
    PRINTF( "SYSCLK %s%10dHz", cmsg6, HAL_RCC_GetSysClockFreq());
    put_rn();
    PRINTF( "HCLK   %s%10dHz", cmsg6, HAL_RCC_GetHCLKFreq());
    put_rn();
    PRINTF( "PCLK1  %s%10dHz", cmsg6, HAL_RCC_GetPCLK1Freq());
    put_rn();
    PRINTF( "PCLK2  %s%10dHz", cmsg6, HAL_RCC_GetPCLK2Freq());
    put_rn();
    put_rn();
    // Check RTC Clock
    PRINTF("--- RTC Clock ---");
    put_rn();
    m1 = (RCC->BDCR >> 8) & 0x03;
    switch (m1) {
        case 0: // no clock
            PRINTF(cmsg7);
            break;
        case 1: // LSE
            PRINTF(cmsg8);
            break;
        case 2: // LSI
            PRINTF("%s 17 to 47, typ.32KHz", cmsg9);
            break;
        case 3: // HSE
            PRINTF( cmsg10 );
            m2 = (RCC->PLLCFGR >> 16) & 0x1f;   // RTCPRE
            m3 = HSE_VALUE / m2;
            PRINTF("%s%10dHz", cmsg6, m3);
            put_rn();
            break;
        default:    // Not come here
            PRINTF(cmsg5);
            break;
    }
    put_rn();
}

int main() {
    char c;
    
    put_rn();
    put_rn();
    PRINTF("Are you ready? (Hit any key)");
    put_rn();
    c = GETC();
    PUTC(c);
    cpu_freq();
    put_rn();
    PRINTF("Repeat -> push RESET button");
    put_rn();
    while(1) {
        myled = 1; // LED is ON
        wait(0.2); // 200 ms
        myled = 0; // LED is OFF
        wait(1.0); // 1 sec
    }
}

#else
#warning "This is only for mbed Nucleo F411RE & F401RE
#endif