Kenji Arai
Check System frequency of Nucleo F411RE board. Also F401RE.
<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".
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I made a clock checking program for Nucleo F411RE and F401 mbed board.
Picture shows F411RE example.
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?
Diff: sys_clock_100MHz_note.h
- Revision:
- 2:e530159dd7aa
diff -r 2d6d2ccd87f8 -r e530159dd7aa sys_clock_100MHz_note.h
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/sys_clock_100MHz_note.h Tue May 12 10:20:38 2015 +0000
@@ -0,0 +1,55 @@
+/*
+ * mbed Application program for the mbed
+ * Nucleo F411RE USB clock sets 48MHz
+ *
+ * Copyright (c) 2015 Kenji Arai / JH1PJL
+ * http://www.page.sannet.ne.jp/kenjia/index.html
+ * http://mbed.org/users/kenjiArai/
+ * Created: May 12th, 2015
+ * Revised: May 12th, 2015
+ *
+ * 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 0
+// file: /mbed-src/targets/cmsis/TARGET_STM/TARGET_STM32F4/TARGET_NUCLEO_F411RE/system_stmf4xx.c
+// line: 611 and floows
+
+<Original>
+ RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
+ RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
+ //RCC_OscInitStruct.PLL.PLLM = 8; // VCO input clock = 1 MHz (8 MHz / 8)
+ //RCC_OscInitStruct.PLL.PLLN = 384; // VCO output clock = 384 MHz (1 MHz * 384)
+ RCC_OscInitStruct.PLL.PLLM = 4; // VCO input clock = 2 MHz (8 MHz / 4)
+ RCC_OscInitStruct.PLL.PLLN = 192; // VCO output clock = 384 MHz (2 MHz * 192)
+ RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV4; // PLLCLK = 96 MHz (384 MHz / 4)
+ RCC_OscInitStruct.PLL.PLLQ = 8; // USB clock = 48 MHz (384 MHz / 8) --> Good for USB
+ if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
+ {
+ return 0; // FAIL
+ }
+
+<Modified>
+ RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
+ RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
+ //RCC_OscInitStruct.PLL.PLLM = 8; // VCO input clock = 1 MHz (8 MHz / 8)
+ //RCC_OscInitStruct.PLL.PLLN = 384; // VCO output clock = 384 MHz (1 MHz * 384)
+ RCC_OscInitStruct.PLL.PLLM = 4; // VCO input clock = 2 MHz (8 MHz / 4)
+#if 0
+ RCC_OscInitStruct.PLL.PLLN = 192; // VCO output clock = 384 MHz (2 MHz * 192)
+ RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV4; // PLLCLK = 96 MHz (384 MHz / 4)
+ RCC_OscInitStruct.PLL.PLLQ = 8; // USB clock = 48 MHz (384 MHz / 8) --> Good for USB
+#else
+ RCC_OscInitStruct.PLL.PLLN = 200; // VCO output clock = 400 MHz (2 MHz * 200)
+ RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV4; // PLLCLK = 100 MHz (400 MHz / 4)
+ RCC_OscInitStruct.PLL.PLLQ = 9; // USB clock = 44.44 MHz (400 MHz / 9) --> Bad for USB
+#endif
+ if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
+ {
+ return 0; // FAIL
+ }
+#endif
\ No newline at end of file