Udayan Mallik

@artvvb
After much experimentation my lwip_echo_server routine is now operational. I can ping an Eclypse Z7 card. Since I use Vitis 2021.2 a large part of online help tends to be useless. I proceeded as follows.
 
1. To confirm that the Realtek PHY chipset can communicate with a Zynq FPGA I used the document found here https://media.digikey.com/pdf/Data Sheets/Digilent PDFs/Eclypse_Z7_HRM_Web.pdf 
2. To use lwip resources I altered the Board Support Package in Vitis.
 A. In the Platform project - Double click the Platform.spr file.
B. Click the ps7_cortex_a9->Zynq fsbl->Board Support Package Tab in the drop down menu.
C. Click on the "Modify BSP Settings ..." tab near the top of the page.
i. In the Overview tab - Select lwip211 libraries.
ii. Then click the Standalone tab.
Set the use_axieth_on_zynq to 0 (since the ZYNQ GEM will be used).
D. Click the ps7_cortex_a9->Standalone on ps7_cortex_a9_0
E. Click on the "Modify BSP Settings ..." tab near the top of the page.
i. In the Overview tab - Select lwip211 libraries.
ii. Then click the Standalone tab.
Set the use_axieth_on_zynq to 0 (since the ZYNQ GEM will be used).
 F. Create a new Application program with the lwip_server_echo option (instead of Hello World) and voila! You have ethernet connection. You can ping IP address 192.168.1.10.

@artvvb Here it is. You are required to modify the "main" routine and the "dacRampDemo" routine as shown below.
void dacRampDemo(float offset, float amplitude, float step, uint8_t channel, uint8_t frequencyDivider, uint8_t gain)
{
    ZMODDAC1411 dacZmod(ZMOD_DAC_BASE_ADDR, DMA_DAC_BASE_ADDR, IIC_BASE_ADDR, FLASH_ADDR_DAC, DMA_DAC_IRQ);
xil_printf("Not Doing anything\n\r");
uint32_t *buf;
float val;
uint32_t valBuf_1, valBuf_2;
int16_t valRaw;
size_t length = (int)(amplitude/step) << 2;
int i;
if (length > ((1<<14) - 1))
{
// limit the length to maximum buffer size (1<<14 - 1)
length = ((1<<14) - 1);
// adjust step
step = amplitude/(length>>2);
}
buf = dacZmod.allocChannelsBuffer(length);
dacZmod.setOutputSampleFrequencyDivider(frequencyDivider);
dacZmod.setGain(channel, gain);
dacZmod.setGain(channel-1, gain);
i = 0;
// ramp up
for(val = -amplitude; val < amplitude; val += step)
{
    valRaw = dacZmod.getSignedRawFromVolt(val + offset, gain);
    valBuf_1 = dacZmod.arrangeChannelData(channel, valRaw);
    valBuf_2 = dacZmod.arrangeChannelData(channel-1, valRaw);
    buf[i++] = (valBuf_1<<16) | (valBuf_2>>16);
}
// ramp down
for(val = amplitude; val > -amplitude; val -= step)
{
    valRaw = dacZmod.getSignedRawFromVolt(val + offset, gain);
    valBuf_1 = dacZmod.arrangeChannelData(channel, valRaw);
    valBuf_2 = dacZmod.arrangeChannelData(channel-1, valRaw);
    buf[i++] = (valBuf_1<<16) | (valBuf_2>>16);
}
// send data to DAC and start the instrument
dacZmod.setData(buf, length);
dacZmod.start();
dacZmod.freeChannelsBuffer(buf, length);
}
int main()
{
    init_platform();
    xil_printf("Hello Eclypse Z7!\n\r");
    //xil_printf("Testing ADC ZMOD...\n\r");     // COMMENTED
    //adcDemo(0, 0, TRANSFER_LEN);            // COMMENTED
    xil_printf("Testing DAC ZMOD...\n\r");
    dacRampDemo(-0.05, 3.90, 0.005, 1, 255, 1);
    cleanup_platform();
    return 0;
}