Starting from ISE Design Suite 14.2, the ps7_init.tcl does NOT enable the
level shifters. Also, in 2.0 silicon the boot ROM does not bring the
PL out of
reset anymore.
It is up to the FSBL, or the user in case of the XMD flow, to enable the level shifter and to bring the PL out of reset
after the bitstream is downloaded.
XMD FLOW The command called "init_user" takes care of the following steps:
Program PS_LVL_SHFTR_EN to 0x0000000F
Program FPGA_RESET_REG to 0x0
This is the new XMD flow starting in 14.2:
fpga -f system.bit
connect arm hw
source ps7_init.tcl
ps7_init
init_user
FSBL FLOW
The following lines of code are used in the FSBL after the download of the bitstream (for both 1.0 and 2.0 silicon)
/* Enable level shifters */
FsblOut32(PS_LVL_SHFTR_EN, 0x0000000F);
/* Enable AXI interface */
FsblOut32(FPGA_RESET_REG, 0);