关于上电时序，可以参考Figure57的时序图，注意reset需要等AVDD/DVDD上电起来至少100us再把reset 拉高。
另外， datasheet Page39中给出了初始化的顺序，按照这个步骤进行下，看在哪个步骤出现问题。
Initialization Sequence
Use the following sequence to power-up and initialize the device:
1. Hold all digital inputs low and ramp up AVDD/DVDD to at least 3 V.
2. Initialize digital inputs and PVDD supply as follows:
• Drive RESET = 0, PDN = 1, and other digital inputs to their desired state while ensuring that
all are never more than 2.5 V above AVDD/DVDD. Wait at least 100 μs, drive RESET = 1,
and wait at least another 13.5 ms.
• Ramp up PVDD to at least 8 V while ensuring that it remains below 6 V for at least 100 μs
after AVDD/DVDD reaches 3 V. Then wait at least another 10 μs.
3. Trim oscillator (write 0x00 to register 0x1B) and wait at least 50 ms.
4. Configure the DAP via I2C (see Users's Guide for typical values).
5. Configure remaining registers.
6. Exit shutdown (sequence defined below).
关于上电时序，可以参考Figure57的时序图，注意reset需要等AVDD/DVDD上电起来至少100us再把reset 拉高。
另外， datasheet Page39中给出了初始化的顺序，按照这个步骤进行下，看在哪个步骤出现问题。
Initialization Sequence
Use the following sequence to power-up and initialize the device:
1. Hold all digital inputs low and ramp up AVDD/DVDD to at least 3 V.
2. Initialize digital inputs and PVDD supply as follows:
• Drive RESET = 0, PDN = 1, and other digital inputs to their desired state while ensuring that
all are never more than 2.5 V above AVDD/DVDD. Wait at least 100 μs, drive RESET = 1,
and wait at least another 13.5 ms.
• Ramp up PVDD to at least 8 V while ensuring that it remains below 6 V for at least 100 μs
after AVDD/DVDD reaches 3 V. Then wait at least another 10 μs.
3. Trim oscillator (write 0x00 to register 0x1B) and wait at least 50 ms.
4. Configure the DAP via I2C (see Users's Guide for typical values).
5. Configure remaining registers.
6. Exit shutdown (sequence defined below).
举报
