MSP430FR2433: I2c fast mode 400kbps

john john

Part Number: MSP430FR2433

Tool/software:

Hello,

Iam using eusci_b0 to run a master i2c @ 100khz which works perfect,i cant seem to get it in fast mode 400khz.iam at the register level setting UCB0RW =40 the chip is running at 16mhz and iam using the SMCLK for SCL.iam not sure what else to try.

1 month ago

0 Zoey Wei 1 month ago

TI__Expert 5160 points

Hi,

What is value of your pull-up resistor?

Regards,

Zoey

0 Zoey Wei 1 month ago in reply to Zoey Wei

TI__Expert 5160 points

Hi,

Make sure your source clock is 16MHz if your Prescaler is 40.

Regards,

Zoey

0 john john 1 month ago

Prodigy 10 points

Hi my pull ups are 4.7k on a pcb no breadboards,and my clock is running @ 16 mhz

0 Bruce McKenney47378 1 month ago in reply to john john

Guru 90450 points

What happens when you run the I2C at 400kHz? Program hang? Incorrect bits?

Since your program is dealing with bytes at 4x the rate, any inadvertent races in your code might be exposed.

0 john john 1 month ago

Prodigy 10 points

My pcb i built has the traces routed wrong for the i2c pins,sorry to waste everyones time i appreciate the help.thanks

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MSP430FR2433: I2c fast mode 400kbps