Kinetis Software Development KitのトピックRe: baud rate 19200 achieved with settings at 16500

baud rate 19200 achieved with settings at 16500

andrewmeyerbti — Thu, 01 Jan 2015 00:39:40 GMT

KDS V2.0.0,

KSDK 1.1.0 Eclipse Update

1.0.0.b141204

com.freescale.processorexpert.ksdk-1.1.0.sp.feature.group

Freescale Semiconductor

Processor Expert for KDS

2.0.0.RT6_b1444-1070

com.freescale.processorexpert.feature.kds.feature.group

Freescale Semiconductor

After some effort I was able to get an ASyncroSerial component to work on my FRDM-KE04Z board by adjusting the component baud rate to 16500 and leaving hyperterminal set at 19200. Living with it for now.

Re: baud rate 19200 achieved with settings at 16500

mjbcswitzerland — Thu, 01 Jan 2015 08:04:35 GMT

Andrew

I have attached a binary for the FRDM-KE04Z as reference which has output on the UART (virtual COM UART 0) at 19200Baud. You can check it as comparison and look at registers with the debugger if needed. I don't use PE or KDS but the settings were made as for any other processor part.

To check are:

1. The PLL runs at 40MHz and the bus clock at 20MHz

2. UART0 is derived from the bus clock and so needs a divide value of 65 (0x41), resulting in a Baud rate of 19'230 (16x oversampling clock)

Check the values that you have from the generated settings to see whether there is an error or whether you maybe set a clock up differently to expected.

Regards

Mark

http://www.utasker.com/kinetis.html

Re: baud rate 19200 achieved with settings at 16500

Jorge_Gonzalez — Tue, 06 Jan 2015 01:59:49 GMT

Hello Andrew:

In addition to help provided by Mark, keep an eye to the internal oscillator frequency. There seems to be a bug not fixed in Processor Expert, which lists by default an Internal Oscillator clock of 32.768 kHz:

The correct trimmed value out of the factory should be 37.5 kHz as stated in the datasheet:

I hope this helps.

Regards!,
Jorge Gonzalez

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