C6748 GPIO程序

查看开发板的硬件原理图，或者硬件手册，另外一个灯与那个pin相连。

再看看GPIODirModeSet这个函数的定义

查看手册，已知led4是GPIO bank6 pin12的，它的pin number 是109，而led3是GPIO bank6 pin13 的，怎么知道它的pin number呢？

“led4是GPIO bank6 pin12的，它的pin number 是109”

对于这个pin number肯定会有定义的地方，看看手册说明或者该函数处的定义

这个地方的寄存器配置，可以参考的地方是技术手册247页

TMS320C6748 DSP
Technical Reference Manual

http://www.ti.com/general/docs/lit/getliterature.tsp?baseLiteratureNumber=spruh79&fileType=pdf

看一下gpio.c里的函数说明和代码实现，就是一个bank 32个GPIO，从低bank往高排的。

/**
* \brief This function gets the direction of a pin which has been configured
* as an input or an output pin.
*
* \param baseAdd The memory address of the GPIO instance being used.
* \param pinNumber The serial number of the GPIO pin.
* The 144 GPIO pins have serial numbers from 1 to 144.
*
* \return This returns one of the following two values:
* 1> GPIO_DIR_INPUT, if the pin is configured as an input pin.
* 2> GPIO_DIR_OUTPUT, if the pin is configured as an output pin.

unsigned int GPIODirModeGet(unsigned int baseAdd, unsigned int pinNumber)
{
unsigned int dir = GPIO_DIR_INPUT;
unsigned int regNumber = 0;
unsigned int pinOffset = 0;

/*
** Each register contains settings for each pin of two banks. The 32 bits
** represent 16 pins each from the banks. Thus the register number must be
** calculated based on 32 pins boundary.
*/

regNumber = (pinNumber - 1)/32;

/*
** In every register the least significant bits starts with a GPIO number on
** a boundary of 32. Thus the pin offset must be calculated based on 32
** pins boundary. Ex: 'pinNumber' of 1 corresponds to bit 0 in
** 'register_name01'.
*/

pinOffset = (pinNumber - 1) % 32;

dir = (HWREG(baseAdd + GPIO_DIR(regNumber)) & (1 << pinOffset));

return (dir >> pinOffset);