AXI GPIO 可以將 PS 端的一個 AXI 4-Lite 接口轉化為 GPIO 接口，並且可以被配置為單端口或雙端口，每個通道的位寬可以獨立配置。
通過使能三態門可以將端口動態地配置為輸入或輸出。
AXIGPIO 是 ZYNQ PL 端的一個 IP 核，可以將 AXI-Lite Master 轉為 GPIO，並且一個 AXI-Lite 接口可以通過 AXI interconnect 模塊控制多個 AXI-GPIO。
AXI-GPIO IP 設置#
最大時鐘頻率#
$Zynq 7020$ 的最大頻率和 $Artix 7-2$ 的速率相同，為 $140 MHz$。
AXI GPIO 設置#
默認為單通道。GPIO 的方向在這裡設置了以後就不能在 vitis 中設置 GPIO 的方向。
中斷屬於 PL 對 PS 的中斷，需要在 ZYNQ 7 Processing System 中勾選
生成的 vitis 的代碼中，xparameters.h 中的 id 默認從 ID 0 開始，不管 vivado 這邊的 AXI-GPIO 的序號是從 0 開始還是從 1 開始。
[!note]
- GPIO 只能使能整個通道中斷，無法單獨使能通道中的某個引腳中斷
中斷類型只能設置為上升沿或高電平
AXI-GPIO 相關代碼#
初始化#
/****************************************************************************/
/**
* 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)
設置輸入輸出方向#
/****************************************************************************/
/**
* 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 讀寫#
/****************************************************************************/
/**
* 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)