Where can I find documentation about clock source numbers?

[rdewaele]

The code example at he end of this post is generated by the clocks tool. (It includes details about the clocks version and processor / package.)
I have no questions about the code itself, but I have failed to find documentation on what number corresponds with what clock source. More specifically, I am asking about the three last lines defined as 2U, 0U and 2U respectively.

Thanks in advance! (And I hope I did not miss something obvious. )

----- code example below -----

/* TEXT BELOW IS USED AS SETTING FOR TOOLS *************************************
!!GlobalInfo
product: Clocks v4.0
processor: MKW41Z512xxx4
package_id: MKW41Z512VHT4
mcu_data: ksdk2_0
processor_version: 3.0.1
board: FRDM-KW41Z
 * BE CAREFUL MODIFYING THIS COMMENT - IT IS YAML SETTINGS FOR TOOLS **********/
/* clang-format on */

#include "fsl_smc.h"
#include "fsl_rtc.h"
#include "clock_config.h"

/*******************************************************************************
 * Definitions
 ******************************************************************************/
#define RTC_OSC_CAP_LOAD_0PF 0x0U /*!< RTC oscillator capacity load: 0pF */
#define SIM_LPUART_CLK_SEL_OSCERCLK_CLK 2U /*!< LPUART clock select: OSCERCLK clock */
#define SIM_OSC32KSEL_OSC32KCLK_CLK 0U /*!< OSC32KSEL select: OSC32KCLK clock */
#define SIM_TPM_CLK_SEL_OSCERCLK_CLK 2U /*!< TPM clock select: OSCERCLK clock */

[marek_neuzil]

Hello,

The comments of these definition contains the name of the clock selector and the selected value, see for example the SIM_LPUART_CLK_SEL_OSCERCLK_CLK definition. It is LPUART0SRCSEL clock selector (in the SIM device) that selects the OSCERCLK clock signal, see the following screenshot of the diagram:

Best Regards,

Marek Neuzil

[rdewaele]

Hello Marek,

Thanks for responding to my question. However, your screenshot does not answer, but does further illustrate what my question is about. I encountered this screen and I noticed that the application knows what numbers correspond with what clock source.

However my question is, how can I know. Is the application the only source of this information? I suspect there are some technical specifications describing this? It just seems a bit weird that you'd need this application to figure out what bits correspond with what clock source.

[marek_neuzil · Accepted solution]

Hello Robrecht,

You can find description of clock selectors and other information in the reference manual, see for example the https://www.nxp.com/docs/en/reference-manual/MKW41Z512RM.pdf  reference manual.

The SIM clock selector values are described in the Chapter 11 System Integration Module (SIM), register definition:

Best Regards,

Marek Neuzil