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sbersin
Visitor
Visitor
6,599 Views
Registered: ‎05-02-2013

ZC702 / 3.3V on VADJ possible ?

Hi all,

 

I want to use IOs of my Zynq (banks 34&35) as LVCMOS33. I configured them in my .ucf constraint file. I checked on board and these are stucked at 2.5V as VADJ rail is configured. I thought I could use the PMBus to configure and power-up the VADJ to 3.3V, but the only possible think seems to go down to 1.2/1.5/1.8v.

 

So is it possible to work in 3.3V ?

 

BR,

 

SB

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8 Replies
austin
Scholar
Scholar
6,589 Views
Registered: ‎02-27-2008

ug850,

 

Vadj ships with it set to 2.5v.  If you wish to set it differently, you will have to read the manual...

Austin Lesea
Principal Engineer
Xilinx San Jose
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eljln
Visitor
Visitor
6,566 Views
Registered: ‎11-20-2007

Dear experts,

 

Anyone has been able to communicate with the PMBUS in zc702 ?   I have been working hard on this using the manual/examples etc but I cannot get it to work even for reading.

 

I do as follows:

 

init and set the mux to the pmbus with:

 

ConfigPtr = XIicPs_LookupConfig(IIC_DEVICE_ID);
if (ConfigPtr == NULL) {
return XST_FAILURE;
}

 

Status = XIicPs_CfgInitialize(&IicInstance, ConfigPtr,
ConfigPtr->BaseAddress);
if (Status != XST_SUCCESS) {
return XST_FAILURE;
}

 

XIicPs_SetSClk(&IicInstance, IIC_SCLK_RATE)

WriteBuffer = 0x80;

 

Status = XIicPs_MasterSendPolled(&IicInstance, &WriteBuffer,1,

MuxIicAddr);

 

ok

 

then

 

I try to read vout (READ_VOUT) command after setting the address to 0x34 for the PM controller.

 


WriteBuffer[0] = (u8) list_of_commands[READ_VOUT];


while (XIicPs_BusIsBusy(&IicInstance));

 

Status = XIicPs_MasterSendPolled(&IicInstance, WriteBuffer,1,IIC_SLAVE_ADDR);

if (Status != XST_SUCCESS) {
return XST_FAILURE;
}



while (XIicPs_BusIsBusy(&IicInstance));

 

 

Status = XIicPs_MasterRecvPolled(&IicInstance, ReadBuffer,
2,IIC_SLAVE_ADDR);
if (Status != XST_SUCCESS) {
         printf("failure\n");
         Status = XIicPs_ReadReg(&IicInstance, XIICPS_SR_OFFSET);
         printf("The status is %x\n", Status);
         Status = XIicPs_ClearOptions(&IicInstance, XIICPS_REP_START_OPTION);
}


 

I think I must be missing some additional commands to be able to read ?

 

Thanks for any hints you can give me.

 

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afarnet
Xilinx Employee
Xilinx Employee
6,559 Views
Registered: ‎10-13-2011

eljln,

zc702 VADJ does support 3.3v. Here is a link of documentation below on how to setup VADJ.
 
 
 
 

Changing the code for the PMBus controllers is not recommended since it can affect the board functionality.
 
Could you open a webcase with Tech Support?
 
 
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eljln
Visitor
Visitor
6,555 Views
Registered: ‎11-20-2007

cannot see the link ...
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afarnet
Xilinx Employee
Xilinx Employee
6,539 Views
Registered: ‎10-13-2011

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eljln
Visitor
Visitor
6,525 Views
Registered: ‎11-20-2007

OK, I have access to that.

 

Basically, I am looking for a solution to read V, I values from the PMBUS directly through the IIC bus in the ZC702. It should be possible but something seems to be broken somewhere. I have raised a webcase to see if Xilinx has had more luck than me.

 

Thanks,

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sylin
Newbie
Newbie
6,457 Views
Registered: ‎06-10-2013

Dear All,

 

I still don't know how to adjust VADJ to 3.3V. Is it possible? How?

BR,

SYLin

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amandaw
Xilinx Employee
Xilinx Employee
6,448 Views
Registered: ‎02-02-2010

AR #51438 provides a step-by-step for changing the power levels on your boards.  Caveat emptor on raising the VADJ level to 3.3v, I recommend reviewing the schematics for any hardware incompatibilities.

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