TI中文支持网The PGA450-Q1 can also be put into a RESET state where the microcontroller is not active. During this state,
SPI is the only digital interface that can be used. The low-side drivers can still be triggered to begin an ultrasonic
burst and the analog front-end and digital data path can still store the returned echo signal in the FIFO RAM.
However, any processing of the FIFO RAM by the internal microprocessor to determine the location of an object
does not occur. The FIFO RAM data can be read over SPI, allowing an external microprocessor to process the
data.
While the microcontroller is active, the MICRO RESET test register is the only register accessible through SPI.
The device must be put into the RESET state before sending additional SPI commands.
The maximum current (VREG not charging) in the RESET state is 15 mA.
To put the microcontroller in reset, write a 1 to bit 0 of the MICRO RESET test register.
To bring the microcontroller out of reset, write a 0 to bit 0 of the MICRO RESET test register
SPI is the only digital interface that can be used. The low-side drivers can still be triggered to begin an ultrasonic
burst and the analog front-end and digital data path can still store the returned echo signal in the FIFO RAM.
However, any processing of the FIFO RAM by the internal microprocessor to determine the location of an object
does not occur. The FIFO RAM data can be read over SPI, allowing an external microprocessor to process the
data.
While the microcontroller is active, the MICRO RESET test register is the only register accessible through SPI.
The device must be put into the RESET state before sending additional SPI commands.
The maximum current (VREG not charging) in the RESET state is 15 mA.
To put the microcontroller in reset, write a 1 to bit 0 of the MICRO RESET test register.
To bring the microcontroller out of reset, write a 0 to bit 0 of the MICRO RESET test register
使用外部MCU控制PGA450进行测距，目前遇到的问题是怎么才能进入SPI模式，
在手册中有这样描述To put the microcontroller in reset, write a 1 to bit 0 of the MICRO RESET test register，意思是通过这样的方式可以进入SPI模式，内部MCU不工作，但是在手册中没有找到 MICRO RESET test register这个寄存器的地址。
还请TI技术人员给予解答帮助，谢谢！
Kailyn Chen：
The micro reset test register address is 0x2F. A value of 0x01 will put the micro in reset and a value of 0x00 will bring the micro out of reset.
LIUQI LAI：
回复 Kailyn Chen:
感谢回复，为什么我在手册中找不到相应的描述，是否有其他的手册可以参考，请指导
Kailyn Chen：
回复 LIUQI LAI:
不好意思，数据手册中确实没有给出这个寄存器的地址，估计在以后新版本的datasheet中会有更新。
LIUQI LAI：
回复 Kailyn Chen:
在哪里可以下载关于PGA450的demo代码
