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PSoC™ 5, 3 & 1

PaKo_4388236
New Contributor

Hi, we have chosen the CY8C9520a GPIO expander for a project. But unfortunately, we have problems with I2C. We have strong pull up in A0 pin, so according to the datasheet, the multiport address is 0x42 (01000010).

But we receive an error: communication timeout. We are running Linux in AM335x. On the pins in I2C bus( SCL, SDA) we have also pull-ups. We tried different pull-ups. Now we have 2k2. It is working at 3.3 Volts.

Even the i2cdetect exports an error (communication timeout).

The connection diagram is simple but we are facing a fundamental problem.

With other peripherals, the i2c bus is working properly. The clock is in 400kHz.

Any ideas what is happening?

tnx in advance.

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1 Solution
SampathS_11
Moderator
Moderator

Hello, Kindly reduce the clock speed to 100kHz as specified in the latest version of the datasheet.

Best regards,

Sampath Selvaraj

View solution in original post

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2 Replies
SampathS_11
Moderator
Moderator

Hello, Kindly reduce the clock speed to 100kHz as specified in the latest version of the datasheet.

Best regards,

Sampath Selvaraj

View solution in original post

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PaKo_4388236
New Contributor

tnx. My mistake.

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