Hi,
Thanks for your inquiry.
"Serial command" means register write, not write in CMD register (0x7E). For example after BMA400 is powered on, it will enter and stay in sleep mode waiting for the command. If you write value of 0x02 to register 0x19 through I2C or SPI serial interface, then BMA400 will enter and stay in normal mode. Similarly, when you write value of 0x01 to register 0x19, BMA400 will enter and stay in low power mode. Please see the attached PDF file as a reference.
Thanks.
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