请教CSM解密过程中的伪读（dummy read）有什么作用？

代码需要执行dummy read，手册TMS320x2833x, 2823x System Control and Interrupts Reference Guide第 4.3.2 Password Match Flow流程图比较清晰看到其作用，CSMSCR最低位仅可读取。通过对DSP2833x_CSMPasswords.asm写入密码，编译后烧录完成对芯片加密。

Even if a device is not protected with a password (all password locations all ones), the CSMwill lock at reset. Thus, a dummy read operation must still be performed on these devices prior to reading, writing, or programming secure memory if the code performing the access is executing from outside of the CSM protected memory region. The Boot ROM code does thisdummy read for convenience.