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AR# 47874

Zynq-7000 AP SoC, Signals - SDIO Three-State Enable Signals on EMIO have the Wrong Polarity

Description

The Unisim names for the three-state enables of the SD data and command signals on EMIO include an 'N' suffix: EMIOSDIOxDATATN and EMIOSDIOxCMDTN. 

This normally indicates an active-Low signal. 

However, these signals are active-High in the Z-7020 GES devices.

Solution

Impact:

Trivial. The polarity of the SD three-state signals are inverted.

Configurations Affected:

Systems that use the SDIO controller via the EMIO interface.

Device Revision(s) Affected: Refer to (Xilinx Answer 47916) - Zynq-7000 AP SoC Silicon Revision Differences Answer Record.


Work-around:
To make these signals active-Low, add inverters to these signals.

This inversion is taken care of in the processing_system7.v wrapper file used by the Vivado/ISE Design Suites:

// EMIO SDIO0 : No negation required as per CR#636210 for 1.0 version of  Silicon,
// FOR Other SI REV, inversion is required
 
assign        SDIO0_CMD_T       =   (C_PS7_SI_REV == "1.0") ? (SDIO0_CMD_T_n) : (~ SDIO0_CMD_T_n);
assign        SDIO0_DATA_T[3:0] =   (C_PS7_SI_REV == "1.0") ? (SDIO0_DATA_T_n[3:0]) : (~ SDIO0_DATA_T_n[3:0]);

Linked Answer Records

Master Answer Records

Answer Number Answer Title Version Found Version Resolved
47916 Zynq-7000 AP SoC Devices - Silicon Revision Differences N/A N/A
AR# 47874
Date Created 05/24/2012
Last Updated 10/17/2014
Status Active
Type Design Advisory
Devices
  • Zynq-7000