Hi.
I would like to ask about how to use mcp4725 on the zybo board.
I want to obtain analog voltage by connecting SDA and SCL signals from MIO14 and 15 of Zybo z7-10 to mcp4725. For this purpose, I wrote the code by referring to 'xiicps_polled_master_example.c', which is an example provided by Xilinx. When I measured the voltage using an oscilloscope, I could see that the Vout of the mcp4725 changed for a while, but I couldn't get the constant value I wanted. How can I control the Vout of the mcp4725? I will attach the code and the photo. Thank you.
ps) Like connecting mcp4725 to Arduino, Can I use the driver provided by adafruit in Vitis?
/////////////////////////////////////////////////////////////////////////////////////////////////
/******************************************************************************
* Copyright (C) 2010 - 2021 Xilinx, Inc. All rights reserved.
* SPDX-License-Identifier: MIT
******************************************************************************/
/*****************************************************************************/
/**
* @file xiicps_polled_master_example.c
*
* A design example of using the device in polled mode as master.
*
* The example uses buffer size 132. Please set the send buffer of the
* Aardvark device to be continuous 64 bytes from 0x00 to 0x3F.
*
* <pre> MODIFICATION HISTORY:
*
* Ver Who Date Changes
* ----- --- -------- -----------------------------------------------
* 1.00a jz 01/30/10 First release
*
* </pre>
*
****************************************************************************/
/***************************** Include Files **********************************/
#include "xparameters.h"
#include "xiicps.h"
#include "xil_printf.h"
/************************** Constant Definitions ******************************/
/*
* The following constants map to the XPAR parameters created in the
* xparameters.h file. They are defined here such that a user can easily
* change all the needed parameters in one place.
*/
#define IIC_DEVICE_ID XPAR_XIICPS_0_DEVICE_ID
/*
* The slave address to send to and receive from.
*/
#define IIC_SLAVE_ADDR 0x62 // default address of mcp4725
#define IIC_SCLK_RATE 100000
/*
* The following constant controls the length of the buffers to be sent
* and received with the IIC.
*/
//#define TEST_BUFFER_SIZE 132
#define TEST_BUFFER_SIZE 132 // Do I have to change this value??
/**************************** Type Definitions ********************************/
/************************** Function Prototypes *******************************/
int IicPsMasterPolledExample(u16 DeviceId);
/************************** Variable Definitions ******************************/
XIicPs Iic; /**< Instance of the IIC Device */
/*
* The following buffers are used in this example to send and receive data
* with the IIC.
*/
u8 SendBuffer[TEST_BUFFER_SIZE]; /**< Buffer for Transmitting Data */
u8 RecvBuffer[TEST_BUFFER_SIZE]; /**< Buffer for Receiving Data */
/******************************************************************************/
/**
*
* Main function to call the polled master example.
*
*
* @return XST_SUCCESS if successful, XST_FAILURE if unsuccessful.
*
* @note None.
*
*******************************************************************************/
int main(void)
{
int Status;
xil_printf("IIC Master Polled Example Test \r\n");
/*
* Run the Iic polled example in master mode, specify the Device
* ID that is specified in xparameters.h.
*/
Status = IicPsMasterPolledExample(IIC_DEVICE_ID);
if (Status != XST_SUCCESS) {
xil_printf("IIC Master Polled Example Test Failed\r\n");
return XST_FAILURE;
}
xil_printf("Successfully ran IIC Master Polled Example Test\r\n");
return XST_SUCCESS;
}
/*****************************************************************************/
/**
*
* This function sends data and expects to receive data from slave as modular
* of 64.
*
* This function uses interrupt-driven mode of the device.
*
* @param DeviceId is the Device ID of the IicPs Device and is the
* XPAR_<IICPS_instance>_DEVICE_ID value from xparameters.h
*
* @return XST_SUCCESS if successful, otherwise XST_FAILURE.
*
* @note None.
*
*******************************************************************************/
int IicPsMasterPolledExample(u16 DeviceId)
{
int Status;
XIicPs_Config *Config;
int Index;
/*
* Initialize the IIC driver so that it's ready to use
* Look up the configuration in the config table,
* then initialize it.
*/
Config = XIicPs_LookupConfig(DeviceId);
if (NULL == Config) {
return XST_FAILURE;
}
Status = XIicPs_CfgInitialize(&Iic, Config, Config->BaseAddress);
if (Status != XST_SUCCESS) {
return XST_FAILURE;
}
/*
* Perform a self-test to ensure that the hardware was built correctly.
*/
Status = XIicPs_SelfTest(&Iic);
if (Status != XST_SUCCESS) {
return XST_FAILURE;
}
/*
* Set the IIC serial clock rate.
*/
XIicPs_SetSClk(&Iic, IIC_SCLK_RATE);
/*
* Initialize the send buffer bytes with a pattern to send and the
* the receive buffer bytes to zero to allow the receive data to be
* verified.
*/
for (Index = 0; Index < TEST_BUFFER_SIZE; Index++) {
SendBuffer[Index] = (Index % TEST_BUFFER_SIZE);
RecvBuffer[Index] = 0;
}
/*
* Send the buffer using the IIC and ignore the number of bytes sent
* as the return value since we are using it in interrupt mode.
*/
Status = XIicPs_MasterSendPolled(&Iic, SendBuffer,
TEST_BUFFER_SIZE, IIC_SLAVE_ADDR);
if (Status != XST_SUCCESS) {
return XST_FAILURE;
}
/*
* Wait until bus is idle to start another transfer.
*/
while (XIicPs_BusIsBusy(&Iic)) {
/* NOP */
}
Status = XIicPs_MasterRecvPolled(&Iic, RecvBuffer,
TEST_BUFFER_SIZE, IIC_SLAVE_ADDR);
if (Status != XST_SUCCESS) {
return XST_FAILURE;
}
return XST_SUCCESS;
}