Xilinx ZYNQ 7000 AXI GPIO 读写/中断

news2024/11/15 15:42:22

打开SDK 后，创建官方例程
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打开官方例程后，会发现这个AXI GPIO设置和 PS MIO/EMIO一模一样

int main(void)
{
	int Status;
	volatile int Delay;

	/* Initialize the GPIO driver */
	Status = XGpio_Initialize(&Gpio, GPIO_EXAMPLE_DEVICE_ID);
	if (Status != XST_SUCCESS) {
		xil_printf("Gpio Initialization Failed\r\n");
		return XST_FAILURE;
	}

	/* Set the direction for all signals as inputs except the LED output */
	XGpio_SetDataDirection(&Gpio, LED_CHANNEL, ~LED);

	/* Loop forever blinking the LED */

	while (1) {
		/* Set the LED to High */
		XGpio_DiscreteWrite(&Gpio, LED_CHANNEL, LED);

		/* Wait a small amount of time so the LED is visible */
		for (Delay = 0; Delay < LED_DELAY; Delay++);

		/* Clear the LED bit */
		XGpio_DiscreteClear(&Gpio, LED_CHANNEL, LED);

		/* Wait a small amount of time so the LED is visible */
		for (Delay = 0; Delay < LED_DELAY; Delay++);
	}

	xil_printf("Successfully ran Gpio Example\r\n");
	return XST_SUCCESS;
}

这是什么情况，那怎么区分AXI GPIO和PS MIO EMIO呢
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在BSP中有gpio和gpiops两个文件夹，分别使用两套函数。

请仔细看下面两个获取gpio实体的函数

XGpioPs_Config *XGpioPs_LookupConfig(u16 DeviceId)
{
	XGpioPs_Config *CfgPtr = NULL;
	u32 Index;

	for (Index = 0U; Index < (u32)XPAR_XGPIOPS_NUM_INSTANCES; Index++) {
		if (XGpioPs_ConfigTable[Index].DeviceId == DeviceId) {
			CfgPtr = &XGpioPs_ConfigTable[Index];
			break;
		}
	}

	return (XGpioPs_Config *)CfgPtr;
}
XGpio_Config *XGpio_LookupConfig(u16 DeviceId)
{
	XGpio_Config *CfgPtr = NULL;

	int Index;

	for (Index = 0; Index < XPAR_XGPIO_NUM_INSTANCES; Index++) {
		if (XGpio_ConfigTable[Index].DeviceId == DeviceId) {
			CfgPtr = &XGpio_ConfigTable[Index];
			break;
		}
	}

	return CfgPtr;
}

没错，AXI GPIO和PS GPIO使用了两套ConfigTable。
两套table 分别定义了不同的实体位置
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也就是说AXI GPIO和PS GPIO使用了两套地址，分别指向了不同的地址。
对于APU来说一切都是地址。

需要注意的是Channel 是AXI GPIO的Channel，在IP生成的时候可以选择 2个通道。
data写入的数据是整个AXI GPIO的位宽。

/****************************************************************************/
/**
* Write to discretes register for the specified GPIO channel.
*
* @param	InstancePtr is a pointer to an XGpio instance to be worked on.
* @param	Channel contains the channel of the GPIO (1 or 2) to operate on.
* @param	Data is the value to be written to the discretes register.
*
* @return	None.
*
* @note		The hardware must be built for dual channels if this function
*		is  used with any channel other than 1.  If it is not, this
*		function will assert. See also XGpio_DiscreteSet() and
*		XGpio_DiscreteClear().
*
*****************************************************************************/
void XGpio_DiscreteWrite(XGpio * InstancePtr, unsigned Channel, u32 Data)
{
	Xil_AssertVoid(InstancePtr != NULL);
	Xil_AssertVoid(InstancePtr->IsReady == XIL_COMPONENT_IS_READY);
	Xil_AssertVoid((Channel == 1) ||
		     ((Channel == 2) && (InstancePtr->IsDual == TRUE)));

	XGpio_WriteReg(InstancePtr->BaseAddress,
			((Channel - 1) * XGPIO_CHAN_OFFSET) + XGPIO_DATA_OFFSET,
			Data);
}