MSP430FR2676: I'm having problems using UCB0 for SPI and USB1 for I2C.

shingo sezaki

Prodigy 80 points

Part Number: MSP430FR2676

Setting 1) eUSCI_B0 → SPI SCLK = P5.5, SIMO = P4.6, SOMI = P4.5 eUSCI_B1 → I2C SDA = P3.2, SCL = P3.6

Setting 2) eUSCI_B0 → SPI SCLK = P5.5, SIMO = P4.6, SOMI = P4.5 eUSCI_B1 → I2C SDA = P4.4, SCL = P4.3

The I2C device worked with Setting 1, but not with Setting 2. Is this pattern wrong?

Setting 1) P3SEL0 |= 0x44; P3SEL1 &= ~0x44;

Setting 2) P4SEL0 |= 0x18; P4SEL1 &= ~0x18;

The main difference is the source code shown above. The I2C slave is the same, only the CPU connection is different.

6 months ago

0 Bruce McKenney 6 months ago

Guru 102955 points

The key is in Note (2) for the Table you posted. You need to add

> SYSCFG3 |= USCIB1RMP; // I2C on P4 not P3

to get the alternate setting.

Looking at your SPI pin settings, I suspect you also need (again according to Note (2)):

> SYSCFG2 |= USCIB0RMP; // SPI on P4/P5 not P1

and you also need to do the P5SEL settings.

0 shingo sezaki 6 months ago

Prodigy 80 points

SYSCFG3 |= USCIB1RMP; Adding this made it work. Thank you. The manual I was looking at didn't have USCIB1RMP as a SYSCFG3 register. Could you tell me which document you looked at?

0 shingo sezaki 6 months ago in reply to shingo sezaki

Prodigy 80 points

Sorry, I looked again and found the section that mentioned it, so the problem was solved.

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MSP430FR2676: I'm having problems using UCB0 for SPI and USB1 for I2C.