在MCF5282上将端口DD用作GPIO

Question

I've got a MCF5282 that I'm trying to use PDD4 as a GPIO on. In my setup code, I've got:

MCF5282_GPIO_DDRDD = 0x10;    /* cs on dd4. */
MCF5282_GPIO_PORTDD = 0x10; /* active-low. */

And in my main loop, I've got:

MCF5282_GPIO_PORTDD = (mainloop_cnt & 0x10);

Which should give me a nice square wave on the oscilloscope, but the port doesn't seem to be doing as I say. Am I missing some setup steps? I can't find anything in the 5282 manual about a “Port DD pin-assignment register” to repurpose it from its “primary” role as DDATA.

Edit 2011-03-01: We never figured this out, we just used a different pin for GPIO.

Answer 1

您可能需要清除芯片配置寄存器中的PSTEN才能禁用DDATA，请参阅《 MCF5282和MCF5216 ColdFire微控制器用户手册》第27-4页