Please tell me why the communication speed, which should be limited by the baud rate, exceeds it.

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Koki
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Hi Support,

Thank you for your usual support.My customer have a question,could you please answer below?

Target:USB-UART Controller CY7C65213

The Internal flash memory is used with default values.
(Meaning that it is not intentionally rewritten by the Utility)
Therefore, I thought that the Baud rate would be limited to the following 115200bps described in the datasheet, but it seems that communication is normally possible with Windows 10 PC <-> USB 12Mbps <-> UART 3Mbps.

https://www.infineon.com/dgdl/Infineon-CY7C65213_USB-UART_LP_Bridge_Controller-DataSheet-v17_00-EN.p...

Koki_0-1677634694979.png

Could you please tell me why it is possible to communicate like this?

Best regards,
Koki

 

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narolkarvarun
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Hi Koki,

you can configure using USB serial configuration utility tool and you can use the USB serial APi .

while you are doing configuration using the serial terminal tool in CDC mode it will send set_line_coding () to device  which will set the configuration soo expected .

Thank you 

Varun Narolkar

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narolkarvarun
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Hi Koki,

you can configure using USB serial configuration utility tool and you can use the USB serial APi .

while you are doing configuration using the serial terminal tool in CDC mode it will send set_line_coding () to device  which will set the configuration soo expected .

Thank you 

Varun Narolkar

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Koki
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Hi Suppoort,
Thank you for answering,but I'm not asking how to change the settings.
Since the default values are used, the communication speed of the device is considered to be limited to BaudRate 115200bps. However, it seems that Windows 10 PC <-> USB 12Mbps <-> UART 3Mbps can communicate normally.
Can you tell me why this situation is happening?
Since UART is asynchronous, communication should not be possible if the Baud rate is different. Device may actually be set to 3Mbps.
 
Best regards,
Koki
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narolkarvarun
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Hi Koki,

can you please let Us know which USB serial Terminal tool you are using for data transfer and testing on a windows PC?

Thank you

Varun Narolkar

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Koki
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Hi Support,

Please tell us about:
The datasheet states that it supports up to 3M BaudRate as shown below.
"CY7C65213/CY7C65213A supports baud rates ranging from 300 baud to 3 Mbaud."
https://www.infineon.com/dgdl/Infineon-CY7C65213_USB-UART_LP_Bridge_Controller-DataSheet-v17_00-EN.p...

But in "Table 2. Internal Flash Configuration for both CY7C65213 and CY7C65213A"
It is listed as "Baud Rate 115200".

Koki_0-1678265984695.png

 

What is the difference? Please tell me the meaning of the value of Baud Rate 115200 and Baud Rate 3M.

The customer's USB serial terminal tool is under review now.

Best regards,
Koki

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narolkarvarun
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Hi koki ,

consider (8N1) UART configuration 115200 is (bits/sec)=115200/(8+1)=12800 bytes/sec.

here,115200 while you configure using USB serial utility tool you can check with our serial SDK Example .  

so while we are using some generic  USB terminal tool will set the configuration using set_line_coding() which is As per CDC standard.

Thank You ,

Varun Narolkar 

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Koki
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Hi Varun-san,

Thank you for your support.
I'm sorry the content of the question was incorrect.
Please answer the following questions.

1. Default Baudrate is 115200 if I don't change the settings? Is this correct?
2. If 1 is correct.
I haven't changed the baud rate setting,why is my device communicating at 3Mbps?

Best regrads,
Koki

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narolkarvarun
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Hi Koki,

1. with  USB Serial configuration Utility tool when you are configuring the 115200 baud rate it will set up the required clock rate.

2.  Now take an example , when  you are setting up serial terminal tool(ex.teraterm) where you are setting up the baud rate microsoft driver will set the configuration using set_line_coding(). which will set up the new baud rate and setting up the clock speed .

3. if you check below image when i configuring 9600bps will send command to USB serial bridge controller to communicate at 9600 baud .

narolkarvarun_0-1679033052920.png

3.after setting baud rate and selecting new setting will send command to set configuration.

check 143 line number in below image.

narolkarvarun_1-1679033573983.png

now let consider when you are selecting 3M in serial tool  will setup the baud rate 3M so its working for you.

Thank You 

Varun Narolkar

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Koki
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Hi Varun-san,

Thank you for your answer.I'm sorry to bother you again.
I I understand your answer.In addition, please confirm the following.

1. Even if default baud rate is 115200, if I change the Teraterm configuration to 9600bps, will the device communicate at a speed of 115200 or higher?
2.If so, what does the default baud rate represent?
From my understanding, I don't think that UART will give a communication speed higher than Baudrate.

Best regards,
Koki

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narolkarvarun
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Hi Koki-San,

As per selecting 115200 baud rate in teraterm will work at 115200, when you selecting 9600 will work at 9600.

its our suggestion when you want to use for Higher speed please configure as per required speed or select max speed 3M.

Thank you

Varun Narolkar

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Koki
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Hi Varun-san,


The USB serial utility (Teraterm) is set to 3Mbps.
On the other hand, since the CY7C65213 internal flash memory has not been rewritten,
It is recognition of 115200bps (default).
Does the setting of Teraterm take precedence over the built-in flash memory?

 

Best regards,

Koki

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narolkarvarun
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Hi Koki-San,

yes, because after the teraterm setting windows, driver sends the command to a device .

Thank you 

Varun Narolkar

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