AXI GPIO 可以将 PS 端的一个 AXI 4-Lite 接口转化为 GPIO 接口，并且可以被配置为单端口或双端口，每个通道的位宽可以独立配置。
通过使能三态门可以将端口动态地配置为输入或输出。
AXIGPIO 是 ZYNQ PL 端的一个 IP 核，可以将 AXI-Lite Master 转为 GPIO，并且一个 AXI-Lite 接口可以通过 AXI interconnect 模块控制多个 AXI-GPIO。
AXI-GPIO IP 设置
最大时钟频率
Z y n q 7020 Zynq 7020 Zynq7020 的最大频率和 A r t i x 7 − 2 Artix 7-2 Artix7−2 的速率相同，为 140 M H z 140 MHz 140MHz。
AXI GPIO 设置
默认为单通道。GPIO 的方向在这里设置了以后就不能在 vitis 中设置 GPIO 的方向。
中断属于 PL 对 PS 的中断，需要在 ZYNQ 7 Processing System 中勾选
生成的 vitis 的代码中，xparameters.h 中的 id 默认从 ID 0 开始，不管 vivado 这边的 AXI-GPIO 的序号是从 0 开始还是从 1 开始。
!note
- GPIO 只能使能整个通道中断，无法单独使能通道中的某个引脚中断
中断类型只能设置为上升沿或高电平
AXI-GPIO 相关代码
初始化
c
/****************************************************************************/
/**
* Initialize the XGpio instance provided by the caller based on the
* given configuration data.
*
* Nothing is done except to initialize the InstancePtr.
*
* @param InstancePtr is a pointer to an XGpio instance. The memory the
* pointer references must be pre-allocated by the caller. Further
* calls to manipulate the driver through the XGpio API must be
* made with this pointer.
* @param Config is a reference to a structure containing information
* about a specific GPIO device. This function initializes an
* InstancePtr object for a specific device specified by the
* contents of Config. This function can initialize multiple
* instance objects with the use of multiple calls giving different
* Config information on each call.
* @param EffectiveAddr is the device base address in the virtual memory
* address space. The caller is responsible for keeping the address
* mapping from EffectiveAddr to the device physical base address
* unchanged once this function is invoked. Unexpected errors may
* occur if the address mapping changes after this function is
* called. If address translation is not used, use
* Config->BaseAddress for this parameters, passing the physical
* address instead.
*
* @return
* - XST_SUCCESS if the initialization is successful.
*
* @note None.
*
*****************************************************************************/
int XGpio_CfgInitialize(XGpio * InstancePtr, XGpio_Config * Config,
UINTPTR EffectiveAddr)设置输入输出方向
c
/****************************************************************************/
/**
* Set the input/output direction of all discrete signals 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 DirectionMask is a bitmask specifying which discretes are input
* and which are output. Bits set to 0 are output and bits set to 1
* are input.
*
* @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.
*
*****************************************************************************/
void XGpio_SetDataDirection(XGpio *InstancePtr, unsigned Channel, u32 DirectionMask)GPIO 读写
c
/****************************************************************************/
/**
* Read state of discretes 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.
* @return Current copy of the discretes register.
* @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.
*****************************************************************************/
u32 XGpio_DiscreteRead(XGpio * InstancePtr, unsigned Channel)
/****************************************************************************/
/**
* 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 Mask 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 Mask)