AXM0F343-64 TCXO Crystal

Hello
We are trying to program AXM0F343-64, the circuit design 26MHz TCXO as reference oscillator, carrier frequency 169MHz
My understanding: AXM0F343-64 is two parts, RF-Transceiver and MCU, TCXO provides stable clock for RF-Transceiver
Question: The MCU part also wants to choose both TCXO as clock instead of choosing to use internal LPOSC and LPXOSC, how do I configure it correctly?

@Putin666

The MCU part also wants to choose both TCXO as clock instead of choosing to use internal LPOSC and LPXOSC, how do I configure it correctly?

Please refer to our community forum thread FAQ at:

@martin.bela
Hello
Thank you for your support, for the problem I’m having I don’t seem to find a solution to the difficulty I’m having from the chip manual and the forum, maybe it’s caused by my misunderstanding, but I need your help.

I understand from the chip manual that Crystal Oscillator (CLKP, CLKN) can provide RF reference oscillator to the transceiver, there is very little introduction on how to use Crystal Oscillator (CLKP, CLKN) in the MCU part. My current problem is that I do not want to use the internal High Speed RC Oscillator, because the external choice of high-precision TCXO, so the MCU also use TCXO clock will be better, right?

I saw the EXTCLK_IN function in the CROSSBAR CONFIGURATION TABLE, which corresponds to GPIOs PA3 and PC1, so I understand that I need to connect from the SYSCLK function pin to EXTCLK_IN through a capacitor to use it?

Ideally, can you tell me how the chip MCU uses external TCXO as clock and which switches can be implemented by software configuration?

Hello
Thank you for your support, for the problem I’m having I don’t seem to find a solution to the difficulty I’m having from the chip manual and the forum, maybe it’s caused by my misunderstanding, but I need your help.

I understand from the chip manual that Crystal Oscillator (CLKP, CLKN) can provide RF reference oscillator to the transceiver, there is very little introduction on how to use Crystal Oscillator (CLKP, CLKN) in the MCU part. My current problem is that I do not want to use the internal High Speed RC Oscillator, because the external choice of high-precision TCXO, so the MCU also use TCXO clock will be better, right?

I saw the EXTCLK_IN function in the CROSSBAR CONFIGURATION TABLE, which corresponds to GPIOs PA3 and PC1, so I understand that I need to connect from the SYSCLK function pin to EXTCLK_IN through a capacitor to use it?

Ideally, can you tell me how the chip MCU uses external TCXO as clock and which switches can be implemented by software configuration?

[

|

黄文波
苏州宙基通信技术有限公司
13625279506
hwb_mail@163.com




|

  • | - |

](头像签名)

---- Replied Message ----

From | Martin via onsemi Community Forumsnotifications@onsemiconductor.discoursemail.com |

  • | - |
    Date | 8/31/2022 03:23 |
    To | hwb_mail@163.com |
    Subject | [onsemi Community Forums] [Connectivity/Sub-GHz] AXM0F343-64 TCXO Crystal |

| martin.bela onsemi Employee
August 30 |

  • | - |

@Putin666

The MCU part also wants to choose both TCXO as clock instead of choosing to use internal LPOSC and LPXOSC, how do I configure it correctly?

Please refer to our community forum thread FAQ at:

@Putin666

TCXO(CLKP, CLKN) 48MHz is used for RF TRANSCEIVER(AX5043), but not in the MCU clock source list with pins and frequency as below.
Five Clock sources for MCU:
• High speed internal RC oscillator (HSOSC): 40MHz/32MHz
• Low power internal RC oscillator (LPOSC): 640Hz
• High speed crystal oscillator (HSXOSC)(HSXOSC_P & HSXOSC_N): 8 - 40 MHz
• Low power crystal oscillator (LPXOSC)(LPXOSC_P & LPXOSC_N): 32.768 kHz
• External clock (RSYSCLK): max. 20MHz

In IDE example, internal RC oscillator (HSOSC) 40MHz is configured as clock source for MCU with initialize() in app.c.

uint8_t Initialize(void)
{
	uint8_t status = FAIL;

	GPIO_Axm0GevkBoardInit();

	status = CMU_Init(CMU_SYSCLK_SEL_HSOSC);

in cmu.h

typedef enum
{
	CMU_HSOSC_32MHz = 0,
	CMU_HSOSC_40MHz = 1
}CMU_HSOSC_FREQ_SEL;

This oscillator can be calibrated to a reference clock for improved performance.
cmu.cfg = CMU_CFG_SYSCLK_HSOSC;

Thank you for using our community forum.