TI中文支持网自制一个AD采样的板子，通过主时钟、帧时钟、位时钟和一个数据线与C6748相连，C6748只做接收功能，但是启动串行器和使能状态机时，GBLCTL寄存器无法写入数据，可能的原因有哪些？
Shine：
请确认一下是否有串行时钟了？
Before GBLCTL is programmed, you must ensure that serial clocks are running. If the corresponding external serial clocks, ACLKX and ACLKR, are not yet running, you should select the internal serial clock source in AHCLKXCTL, AHCLKRCTL, ACLKXCTL, and ACLKRCTL before GBLCTL is programmed. Also, after programming any bits in GBLCTL you should not proceed until you have read back from GBLCTL and verified that the bits are latched in GBLCTL.
www.ti.com/…/spruh79c.pdf另外一定要回读GBLCTL寄存器确保数据写进去了。
5.4.1 You Did Not Read Back From GBLCTL After Writing to GBLCTL
www.ti.com/…/sprack0.pdf
huanhuan zhang：
回复 Shine:
你好，我只需要接收，接了ACLKR，AFSR，AHCLKR以及数据接口AXR[12]，ACLKR，AFSR，AHCLKR这几个时钟是有的，这几个时钟由ADC音频芯片AK5574输出。
Shine：
回复 huanhuan zhang:
请看一下在操作GBLCTL寄存器之前，在代码或者GEL文件里有没有PSC使能mcasp？
