iMX1064 Crystal required? SWD support

[Harjit]

Clocking

My design is severely board space constrained. The latest reference manual (IMXRT1064RM, Rev 0.1, 12/2018), section 14.4.3 RC Oscillator (24 MHz) says:

A lower-power RC oscillator module is available on-chip as a possible alternative to the
24 MHz crystal oscillator after a successful power-up sequence.

I don't need precise timing in my system. I'd love to eliminate the external oscillator / crystal and use this built in circuit. Has anyone succeeded in doing this?

For the 32kHz, I don't need precision. Section 14.5.1 says:

The internal oscillator is automatically multiplexed in the clocking system when the
system detects a loss of clock.

This gives me hope that I can not use a 32kHz crystal/oscillator and be fine. Yes?

SWD

The latest reference manual (IMXRT1064RM, Rev 0.1, 12/2018), section 1.3 says:

• Support for 5-pin (JTAG) and SWD debug interfaces

Doing a search for SWD, I can see how to route the signal but I don't see any more details. Does anyone have SWD working?

Thanks in advance.

[victorjimenez]

Hello,

Regarding your questions please see my comments below.

I don't need precise timing in my system. I'd love to eliminate the external oscillator / crystal and use this built in circuit. Has anyone succeeded in doing this?

I'm currently checking with the design team what would be the implications of not having an external oscillator/crystal, and if it's a recommended implementation. I will give you the update on the following days.

This gives me hope that I can not use a 32kHz crystal/oscillator and be fine. Yes?

When a high-accuracy real-time clock is not required, the system may use the on-chip 40-kHz oscillator. The tolerance is ±50 %. If RTC_XTALI is tied to GND and RTC_XTALO is floating, the on-chip oscillator is engaged automatically.

Doing a search for SWD, I can see how to route the signal but I don't see any more details. Does anyone have SWD working?

In the RT1064-EVK, the RT is programed through SWD from the Free-Link interface. I highly recommend you taking a look at the evaluation board schematics (link).

Have a great day,
TIC

-------------------------------------------------------------------------------
Note:
- If this post answers your question, please click the "Mark Correct" button. Thank you!

- We are following threads for 7 weeks after the last post, later replies are ignored
Please open a new thread and refer to the closed one, if you have a related question at a later point in time.
-------------------------------------------------------------------------------

[victorjimenez]

Hello, 

Sorry for the late response. Regarding your first question, is not possible to use only the internal RC oscillator. The part expects a crystal when booting, so one would need an external crystal in the system anyway. The 24MHz RC should only be used for low power modes (shut off the external OSC to save some power). 

Best regards, 

Victor