cancel
Showing results for 
Search instead for 
Did you mean: 
Highlighted
Contributor
Contributor
424 Views
Registered: ‎06-18-2019

Using Xspi_Transfer I am getting delay for CS to go High after data transfer

Using Xspi_Transfer I am getting delay for CS to go High after data transfer i am get around 1 clk cycle delay how can i reduce the delay i want the cs to go high immediately after data transfer

Capture.PNG
0 Kudos
7 Replies
Highlighted
Scholar
Scholar
402 Views
Registered: ‎04-13-2015

Re: Using Xspi_Transfer I am getting delay for CS to go High after data transfer

@prashanth_makam 

The SPI has a register controlling 4 different delays (Delay_Reg), but sadly for you, the delay between the last bit & CS deasserted is not in there / modifiable.

0 Kudos
Highlighted
Contributor
Contributor
400 Views
Registered: ‎06-18-2019

Re: Using Xspi_Transfer I am getting delay for CS to go High after data transfer

Then how can i reduce the Delay is there any register level code for SPI transfer 

0 Kudos
Highlighted
Moderator
Moderator
344 Views
Registered: ‎04-09-2019

Re: Using Xspi_Transfer I am getting delay for CS to go High after data transfer

Hi Prashanth,

We don`t have any specific register to define the delay between the data transfer and CS to be deasserted.

It is always depends on when you are deasserting the CS after the data transfer.

Regards,

Venu

0 Kudos
Highlighted
Contributor
Contributor
307 Views
Registered: ‎06-18-2019

Re: Using Xspi_Transfer I am getting delay for CS to go High after data transfer

The Chip select is controlled  by hardware i am not doing anything  below is the thing iam doing 

 

Tx_Buffer[0]= 0xFF;
Tx_Buffer[1]= 0x01;
Tx_Buffer[2]= 0x02;
Tx_Buffer[3]= 0xAA;

XSpi_SetSlaveSelect(&SPI_SpiInstance,0x00000001);

XSpi_Transfer(&SPI_SpiInstance,Tx_Buffer ,Rx_Buffer,4);

XSpi_SetSlaveSelect(&SPI_SpiInstance,0x00000000);

0 Kudos
Highlighted
Scholar
Scholar
264 Views
Registered: ‎04-13-2015

Re: Using Xspi_Transfer I am getting delay for CS to go High after data transfer

@prashanth_makam 

Are you sure you've set the CS in auto mode and did not left it in the default manual mode? If it is still the manual mode then a delay of ~1us can be expected.

0 Kudos
Highlighted
Contributor
Contributor
261 Views
Registered: ‎06-18-2019

Re: Using Xspi_Transfer I am getting delay for CS to go High after data transfer

I am using Xspi set slave select function before transferring the data and CS is controlled by master core logic

0 Kudos
Highlighted
Moderator
Moderator
176 Views
Registered: ‎04-09-2019

Re: Using Xspi_Transfer I am getting delay for CS to go High after data transfer

Hi,

There is some standard after how much time we should start the data transfer, it should not be immediatly after asserting the CS.

Regards,

Venu

0 Kudos