TCA9539-Q1: about switching port issue

Lawrence He

Expert 2900 points

Part Number: TCA9539-Q1

Tool/software:

Hi, Support Team

our client use TCA9539-Q1 have two question as blow:

Q1: about I/O expander port to port switching the maximum rate?

Q2: Could possible fine tune I2C can effect switching port rate?

because its effect our software task process

if any suggestion, Please advise me.

Thanks,

Best regards,

Lawrence

4 months ago

0 Clemens Ladisch 4 months ago

Guru 275980 points

The port can switch as fast as you can write to the output register, i.e., the speed is limited by your I²C master.

What is the actual problem you're trying to solve? An SPI-controlled shift register or a PWM LED driver might be a better solution.

0 Tyler Townsend 4 months ago

TI__Mastermind 30213 points

Hi Lawrence,

Thank you for your question. Please let me know if Clemens answered your question?

Regards,

Tyler

0 Lawrence He 4 months ago in reply to Clemens Ladisch

Expert 2900 points

Hi, Clemens

thank you for reply, if we send out I2C package, how many time required logic level from low to high?

if any suggestion, Please advise me.

Thanks,

best regards,

Lawrence

+1 Clemens Ladisch 4 months ago in reply to Lawrence He

Guru 275980 points

With three bytes for a register write, 9 bits per byte, ignoring start/stop conditions, and a 400 kHz clock, this would result in a rate of about 14 kHz. Due to software overhead, the actual rate is likely to be lower, and cannot be easily controlled.

0 Tyler Townsend 4 months ago in reply to Lawrence He

TI__Mastermind 30213 points

Hi Lawrence,

Lawrence He said:
thank you for reply, if we send out I2C package, how many time required logic level from low to high?

What exactly is your question here?

Regards,

Tyler

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TCA9539-Q1: about switching port issue