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Altera_Forum's avatar
Altera_Forum
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14 years ago

A problem on I2C, which may cause by the pin to pin resistance on the emulation board

Dear Sir, I met one problem as the attachment. The voltage drop is supposed caused by the pin to pin impedance, I guess. Because pin to pin resistance is about ony 30K to 40K Ohms which is...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
14 years ago

From your draqing: Problably the pull up on the SDA/SCL line is too high. For most I2C busses the internal pull ups of fpga's are to high in value. A 4.7kOhm pull up on the lines is a good starting point. Or some device is loading the bus ...