LMK04828 Not Responding to SPI

Also Please help me to find on which pin I can read back the Register values

Hi Timothy,

Thank you very much for the response and also for the document.

RESET(pin5) is pulled down and also probed correctly as low.

We are using EMIO Pins of ZCU102 Board for SPI Programming and Please find our programming sequence below. Please verify and give your valuable comments:

#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <unistd.h>
#include <fcntl.h>
#include <linux/types.h>
#include <linux/spi/spidev.h>

#define RESET_CMD 0x000080
#define NORMAL 0x000010
#define DCKOD 0x010010
#define DCKOB 0x010302
#define DCKFMT 0x010701
#define VCOMX 0x013800
#define FIXED1 0x01457F

#define CLKINEN 0x01461A
#define CLKINS 0x01471A
#define CLKINS1 0x014802
#define CLKINS2 0x014942
#define PLL1N1 0x01533D
#define PLL1N2 0x015409
#define PLL1CP 0x015BDF
#define PLL2R1 0x016000
#define PLL2R2 0x016102
#define PLL2PRE 0x016269
#define FIXED2 0x0171AA
#define FIXED3 0x017202
#define FIXED4 0x017C15
#define FIXED5 0x017D33
#define PLL2N1 0x016600
#define PLL2N2 0x016700
#define PLL2N3 0x01680B
#define PLL2CP 0x016959
#define LP2R4R3 0x016C00
#define LP2C4C3 0x016D00

int load_config(unsigned int cmd, int fd)
{
int ret;
uint8_t RecvBuf;
ret = write(fd,&cmd,6);
if (ret < 0)
{
printf("error writing data \n");
exit (0);
}
/*ret = read(fd,&RecvBuf,3);
if(ret < 0)
{
printf("error reading data \n");
exit(0);
}
printf("Received Value: %d\n",RecvBuf);
return RecvBuf;*/
return 0;
}

int readback(unsigned int cmd, int fd)
{
int ret;
uint8_t RecvBuf;
ret = write(fd,&cmd,2);
if (ret < 0)
{
printf("error writing data \n");
exit (0);
}
ret = read(fd,&RecvBuf,1);
if(ret < 0)
{
printf("error reading data \n");
exit(0);
}
printf("Received Value: %x\n",RecvBuf);
//return RecvBuf;
return 0;
}

int main(int argc, char **argv)
{
printf("Hello World!\n");
int stop=0;
int fd,ret;
int fch=1;
fd = open("/dev/spidev1.0",O_RDWR);
if (fd < 0)
{
printf("error opening node \n");
exit (0);
}
else
{
do
{
printf("Specify the Output Frequency: (1->161Mhz 2->156Mhz 3->195MHz 4->257MHz 5->Read Back 6->Stop 7->Iverase Read Back: \n");
scanf("%d",&fch);
switch(fch) {

case 1:
printf("Output Frequency: 161.1328125Mhz\n");
load_config(RESET_CMD,fd);
load_config(NORMAL,fd);
load_config(DCKOD,fd);
load_config(DCKOB,fd);
load_config(DCKFMT,fd);
load_config(VCOMX,fd);
load_config(FIXED1,fd);
load_config(0x014A33,fd);
load_config(CLKINEN,fd);
load_config(CLKINS,fd);
load_config(CLKINS1,fd);
load_config(CLKINS2,fd);
load_config(PLL1N1,fd);
load_config(PLL1N2,fd);
load_config(PLL1CP,fd);
load_config(PLL2R1,fd);
load_config(PLL2R2,fd);
load_config(PLL2PRE,fd);
load_config(FIXED2,fd);
load_config(FIXED3,fd);
load_config(FIXED4,fd);
load_config(FIXED5,fd);
load_config(PLL2N1,fd);
load_config(PLL2N2,fd);
load_config(PLL2N3,fd);
load_config(PLL2CP,fd);
load_config(LP2R4R3,fd);
load_config(LP2C4C3,fd);
printf("Write Completed\n");
break;
case 2:
printf("Output Frequency: 156.25Mhz\n");
break;
case 3:
printf("Output Frequency: 195.3125Mhz\n");
break;
case 4:
printf("Output Frequency: 257.8125Mhz\n");
break;
case 5:
printf("Readback\n");
load_config(0x000080,fd);
load_config(0x000010,fd);
load_config(0x01457F,fd);
load_config(0x014A33,fd);
load_config(0x0171AA,fd);
load_config(0x017202,fd);
load_config(0x017C15,fd);
load_config(0x017D33,fd);

load_config(0x014833,fd);
load_config(0x014973,fd);
load_config(0x015F3B,fd);
load_config(0x016E3B,fd);

readback(0x8003,fd);
break;
case 7:
load_config(0x800000,fd);
load_config(0x100000,fd);
load_config(0x7F4501,fd);
load_config(0x334A01,fd);
load_config(0xAA7110,fd);
load_config(0x027201,fd);
load_config(0x157C01,fd);
load_config(0x337D01,fd);

load_config(0x334801,fd);
load_config(0x734901,fd);
load_config(0x3B5F01,fd);
load_config(0x3B6E01,fd);

readback(0x0380,fd);
break;
case 6:
stop=1;
break;
default:
printf("Choose a Valid Option\n");
}
}while(stop==0);

}

return 0;
}

Hi Timothy,

Good news, I could communicate with LMK04828 through SPI and I can Write the registers and also read what I write through 4-wire mode.

I am using a custom Board. Using the parameters as below:

Oscin : 156.25Mhz

CLKin: 30.72MHz

I am expecting 156.25MHz LVDS output through DCLKOUT1

Also attaching the Clock design tool output for my configurations.

Please Help to get possible register configurations for this if you have any or please suggest which all registers are need to be taken care.

Thanks in Advance

Nikhil Krishnan R

Hi

Please find our register set values below:

0x100 -> 0x10
0x103 -> 0x02
0x106 -> 0x71
0x107 -> 0x01
0x138 -> 0x01
0x146 -> 0x1A
0x147 -> 0x1A
0x148 -> 0x03
0x149 -> 0x43
0x150 -> 0x43
0x155 -> 0x0C
0x156 -> 0x00
0x159 -> 0x3D
0x15A -> 0x09
0x160 -> 0x00
0x161 -> 0x02
0x162 -> 0x49
0x166 -> 0x00
0x167 -> 0x00
0x168 -> 0x10
0x169 -> 0x59
0x16C -> 0x00
0x16D -> 0x00

All other registers are with default value

Please verify and suggest changes.
Please help me, this is something urgent.

Hi Timothy,

Very glad to say that we got the output frequency well.

Initial Programming sequence was done as per the datasheet.

Problem was with Frequency Doubler and Charge pump gain. We gave the register values as suggested and got the output.

Our input is 3.3VDC CMOS signal to CLKIN1 and got LVDS output at DCLKOUT1.

Is there any register to be configured to increase the stability of the output frequency?