Kinetis Microcontrollers中的主题 Re: Explanation of KL43Z features (ROM bootloader and USB crystal-less operation)

Explanation of KL43Z features (ROM bootloader and USB crystal-less operation)

piotrcerba — Sun, 23 Aug 2015 21:07:00 GMT

Hello, while reading about KL43Z I stumbled across this article Unboxing the Freescale FRDM-KL43Z Board | MCU on Eclipse by Erich Styger.

I wanted to ask what are the benefits/drawbacks of this separate ROM bootloader and crystal-less USB operation in comparison with eg. KL46Z.

Why are LDD not supported? What limitations does it put?

Re: Explanation of KL43Z features (ROM bootloader and USB crystal-less operation)

Hui_Ma — Mon, 24 Aug 2015 03:22:26 GMT

Hi,

The ROM Bootloader will provides USB/I2C/SPI/LPUART bootloader without related code development processing and customer can use full Flash range for application (if customer using bootloader software, which need to occupied some range of Flash memory).

The crystal-less USB module brings obviously benefit for customer to reduce the BOM cost.

The KSDK V1.2.0 supports FRDM-KL43Z board with related HAL/Peripheral driver.

I don't think Processor Expert LDD component missing could affect FRDM-KL43Z board application.

More detailed info about KSDK for KL43Z could be found here.

Wish it helps.

Have a great day,
Ma Hui

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Re: Explanation of KL43Z features (ROM bootloader and USB crystal-less operation)

mjbcswitzerland — Mon, 24 Aug 2015 12:24:55 GMT

Crystal-less operation:

1. Saves costs because no crystal or oscillator is required

2. Restrictions:

- USB host is not possible (device is)

- Since the IRC48M is not synchronised when USB is not connected, the processor's time base (for timing, generating clocks, Baud rates) will not be as accurate (also have more temperature drift) as when there is an accurate reference available.