i2c device not working on 1.8v in LPC EVK

[jinu_mohan]

Hi team,

we are working on LPCXpresso55S69/55S28 Development Boards in that we have loaded the sdk lpcxpresso55s28_i2c_read_accel_value_transfer in this example we are able to read accelerometer values 

output

but wen we changed jumper p4 into 1.8v the accelero meter is not working ,from controller we are not able to receive any clock pulse.(we checked via oscilloscope) . and  also we are not able to get any logs in debugger we are getting debug print as below 

is there any settings needs to be changed in EVK or circuit or in code settings please let us know.

we didn't changed any configurations in example code ! 

EVK we are using

@Blackpearl  @ZhangJennie

@Eiffel   @Kp_krishna 

[xiangjun_rong · Accepted solution]

Hi,

The SDK example lpcxpresso55s28_i2c_read_accel_value_transfer reads the MMA8652FC, 3-Axis, 12-bit, Digital Accelerometer, as you can see the screenshot, the VDD of MMA8652FC ranges from 1.96V to 3.6V, the VDDIO of MMA8652FC ranges from 1.62V to 3.6V. On our LPC55S69-EVK board, the VDD pin and VDDIO pin of MMA8652FC are both connected to VDD_TARGET node, which is 1.8V when you use 1.8V power supply, that is why the MMA8652FC can not work because the VDD is required 1.96V at least.

Hope it can help you

BR

XiangJun Rong