J721E EVM Hardware Architecture
56
SPRUIS4A – December 2019 – Revised May 2020
Copyright © 2019–2020, Texas Instruments Incorporated
Jacinto7 J721E/DRA829/TDA4VM Evaluation Module (EVM)
Hot plug
: The PRSNT1# and PRSNT2# signals are the hot plug presence detect signals. The PRSNT1#
is pulled up and PRSNT2# is connected to GPIO expander, so that PRSNT1# will be pulled low when a
add on card is plugged in as both the PRSNT signals in add on cards will be shorted. Optional resistor is
provided to short the PRSNT1# and PRSNT2# to support host and device mode.
For choosing Host or device operation of PCIe card, following resistors must be mounted/unmounted as
mentioned in
.
Table 30. Resistors for Selecting PCIe Card Host or Device Operation
Mode
Mount
Demount
Host mode
R674
R675
R679
Device mode
R675
R674
R679
Additional Options:
Optional MDIO bus and USB2.0 interface is supported for external PCIe add on cards.
SoC Main domain (CPSW9G0) MDIO signals are interfaced to the x1L PCIe Socket (J11) through 0-
Ω
inline resistors (R137 and R136) when network (Ethernet) based add on cards inserted into J11. The path
is disconnected by default.
Also, USB2.0 data signals from USB HUB downstream port is interfaced to 4 pin header (J2) and the 5 V
supply is provided through the load switch.
Figure 37. USB2.0 Header Connection