CY7C65211A Unintentional frequency change

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hata_3396041
Level 4
Level 4
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Hello

I am trying to connect an Android device to a board using CY7C65211A.

The CY7C65211A is used by setting it to SPI Master mode (speed = 3MHz) with the Cypress USB-Serial Configuration Utility.

On a specific host (Android device), the SPI communication speed becomes 9600Hz by setting dwDTERate = 9600 with

the CDC SET_LINE_CODING command in the enumeration process when connected via USB, and the desired data rate (3MHz) ) Will not be able to communicate.

However, this is because the CY7C65211A is a Fixed FW, so I think it works as specified.

Please tell me about two.

●Would you please tell me if there is a method that can be used without slowing down the SPI communication speed by a command from the Android tablet side?

●Even if the speed of serial communication (SPI communication) changes when the USB CDC command set line coding is sent from the tablet side, the speed of USB transfer itself does not change. Is this my perception correct?

Best Regards

Hayato

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1 Solution
YatheeshD_36
Moderator
Moderator
Moderator
750 replies posted 500 replies posted 250 solutions authored

Hello,

1. Would you please tell me if there is a method that can be used without slowing down the SPI communication speed by a command from the Android tablet side?

In you are using SPI in CDC mode and standard terminals from the host side. You cannot change the frequency in any other way.  It is set from the terminal.

If you have a custom host application, then the  CySetSpiConfig_VCP APi can be used to set the frequency.

2. Even if the speed of serial communication (SPI communication) changes when the USB CDC command set line coding is sent from the tablet side, the speed of USB transfer itself does not change. Is this my perception correct?

Yes, the speed of the USB will remain the same. Only the SPI interface frequency is affected.

Thanks,

Yatheesh

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1 Reply
YatheeshD_36
Moderator
Moderator
Moderator
750 replies posted 500 replies posted 250 solutions authored

Hello,

1. Would you please tell me if there is a method that can be used without slowing down the SPI communication speed by a command from the Android tablet side?

In you are using SPI in CDC mode and standard terminals from the host side. You cannot change the frequency in any other way.  It is set from the terminal.

If you have a custom host application, then the  CySetSpiConfig_VCP APi can be used to set the frequency.

2. Even if the speed of serial communication (SPI communication) changes when the USB CDC command set line coding is sent from the tablet side, the speed of USB transfer itself does not change. Is this my perception correct?

Yes, the speed of the USB will remain the same. Only the SPI interface frequency is affected.

Thanks,

Yatheesh

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