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PSoC 5, 3 & 1 MCU

qizh_1205111
New Contributor

Hi

i want to configure a pin as both input and output, such emulate SDA of i2c master,  what driver mode should i use to make it work ?

i tried strong driver/ pull up/down, found output works fine but input can't read right value in strong driver mode,

and in pull up/down, output can't driver right voltage.

appreciate your help and sharing your experience, thanks.

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1 Solution
JoMe_264151
Expert II

Use "Open Drain drives low" and an external pull-up resistor (5k), set initial drive state to "high". This is what I2C uses.

Bob

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3 Replies
JoMe_264151
Expert II

Use "Open Drain drives low" and an external pull-up resistor (5k), set initial drive state to "high". This is what I2C uses.

Bob

View solution in original post

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GeonaP_26
Moderator
Moderator

Hello Qipeng,

For more details, please make use of section Internal I2C Bus Multiplexing of I2C Master/Multi-Master/Slave datahseet.

Best Regards,

Geona Mary

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qizh_1205111
New Contributor

Thanks all your answers. finally i found i2c controller can use external clock to get a very low i2c speed(<10K),  so don't need to emulated i2c any more.  only 50K/100K is supported for internal clock mode(i selected before).

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