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Hello,
I am developing a hall sensor EVM and for that I need to use some LED light indicators that I plan switch on and off with my GPIO expander that is controlled by the MSP430FR4133. The GPIO expander is controlled through I2C. It appears that I am getting a peculiar situation where the SDA drops the first bit or leads the SCL. I first tried sending the signal to the GPIO device (TCA9535) and then to a voltage divider (10k and 9Meg from Vcc to GND) emulating the open drain. In each case the signals are essentially the same, so I am convinced it has something to do with the setup of the MSP430. I modified the sample code you all provide: msp430fr413x_euscib0_i2c_15.c, such that it would send the addresses: 0x4E, 0x47, 0x8E, or 0x87. The leading 0 of 0x4E, 0x47 appears to be dropped as well as the leading 1 of 0x8E,0x87. All of these measurements were done with a slower frequency (UCB0BRW = 0x82;) . However, I also repeated at the original frequency as well and the result seemed the same. Do you know how I can fix this problem?
Figure 1: Address: 0x4E, UCB0BRW = 0x8;
Fig. 2 Address: 0x4E, UCB0BRW = 0x82;
Fig. 3 Address: 0x4E, UCB0BRW = 0x82;
Fig. 4 Address: 0x87, UCB0BRW = 0x82;
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