I can't change baud rate above 9600 on SC18IM700

[Kuro19]

I have SC18IM700 and I tried to change its baud rate with teraterm macro.

I executed ttl file with command

"send $57$00$30$50"
"send $57$01$00$50"
"send $52$00$01$50"

I want to change baud rate to 115200 bad I recieved "OK" and its baud rate always become default value(9600).

A change to 9600 bps or less will succeed, but values above 9600 will revert to the default value.

Please tell me how to change baud rate.

I'm sorry for my poor English.

[guoweisun]

The baud rate generator is an 8-bit counter that generates the data rate for the transmitter
and the receiver. The rate is programmed through the BRG register and the baud rate can
be calculated as follows:

(1)

Remark: To calculate the baud rate the values in the BRG registers must first be
converted from hex to decimal.
Remark: For the new baud rate to take effect, both BRG0 and BRG1 must be written in
sequence (BRG0, BRG1) with new values. The new baud rate will be in effect once BRG1
is written.

[Kuro19]

Thank you for your answer.

However, I already know this information and have done the calculations.

I wrote 0x03 to BRG0 and 0x00 to BRG1 but SC18IM700 returned "0x4F4B(OK)" and its value reseted.

This happens when I try to set it above 9600.

[guoweisun]

Both BRG0 and BRG1 must be written in sequence (BRG0, BRG1) with new values.

[Kuro19]

That is how we do it.
We have currently succeeded in setting 9600 bps or less.
We have referred to all the datasheets and performed the appropriate operations, so we would be grateful for any information not found in the datasheets.

[guoweisun]

Can you share with your schematic here?

[Kuro19]

Please see attached file

[guoweisun · Accepted solution]

Looks no issue for your schematic.

[Kuro19]

Thank you for your confirmation.

It seems difficult to set the baud rate above 9600, so I would like to find another way.
Thank you very much.

[guoweisun]

After your write related registers value do you read them again for confirm?

[Kuro19]

Yes.

After receiving "OK", I read it again and the result was the initial value (0xF002).

All other register values are also returned to their initial values.