Kinetis Design StudioのトピックRe: processor expert bug - UART baud rate

processor expert bug - UART baud rate

zohargolan — Sat, 11 Jun 2016 00:26:48 GMT

I had to set up uart with 2 modes of operation, one in 115200bps and one in higher baud rate.

When I’ve set the second mode to be 921600bps, it was working fine, but when I set it to be 3250000bps, the transmission was actually at ~900kbs instead.

Found out in file ASerialLdd2.c
in function ASerialLdd2_SelectBaudRate there
is an array holding the possible values for register UART2_C4 field BRFA and registers UART2_BDH and UART2_BDL

BD is holding the baudrate divider and BRFA is holding the fine adjustment value.

The calculation is

Baudrate = UART
device clock/(16*(BD+BRFA/32)) = 96MHz/(16*(BD+BRFA/32))

The original lines were

static const uint8_t ASerialLdd2_BaudAdjustValueSpeed0[0x02] = {0x02u,0x10u};

static const uint16_t ASerialLdd2_BaudDivisorSpeed0[0x02] = {0x34u,0x06u};

This gave ~900Kbps to mode 1

The modified lines are

static const uint8_t ASerialLdd2_BaudAdjustValueSpeed0[0x02] = {0x02u,0x1bu};

static const uint16_t ASerialLdd2_BaudDivisorSpeed0[0x02] = {0x34u,0x01u};

This gives 3250000bps to mode 1 (as intendant)

Why is that?

Thanks,

Zohar

Re: processor expert bug - UART baud rate

Alice_Yang — Sun, 12 Jun 2016 03:07:24 GMT

Hello Zohar,

Please tell me the part number of your chip, the version of KDS,

also the core clock an bus clock .

then i will check it on my side, thank .

Alice

Re: processor expert bug - UART baud rate

zohargolan — Mon, 13 Jun 2016 16:43:12 GMT

Hi Alice,

Device number MK20DN512VMC10

KDS version 3.0.0

Core clock 95.977472 MHz

Bus Clock 47.988736 MHz

Thank you,

Zohar

Re: processor expert bug - UART baud rate

Alice_Yang — Tue, 14 Jun 2016 09:10:39 GMT

Hello Zohar,

Are you sure the code you shown is generated by PE ?

On my side , i also create one project , then add the UART component ,

while i have not find the code you side , could you send your project to me ?

On my side , it is like this :

Alice

Re: processor expert bug - UART baud rate

zohargolan — Tue, 14 Jun 2016 16:03:45 GMT

Hi Alice.

This is the code snippet I have

I am using two different baud rates in different mode. I don't think you've setup the UART the same

Best regards,

Zohar

Re: processor expert bug - UART baud rate

Alice_Yang — Wed, 15 Jun 2016 07:39:27 GMT

Hi ZOHAR,

Yes, i use the KDSv3.0 , and add the UART component , then configure it .

And maybe the version if different between us, so please send your project to me .

Or i don't know how to generate your code.

Or another method is you can use the code you changed .

Alice