Datasheet

TMS
TDI
TDO
PD
RTCK
TCK
EMU0
TRST
TDIS
GND
KEY
GND
GND
EMU1
GND
TCK
TDO
TDI
TMS
TRST
GND
1
2
3 4
5 6
7 8
9 10
11 12
1413
3.3 V
3.3 V
100 W
2.2 kW
4.7 kW4.7 kW
3.3 V
Distance between the header and the target
should be less than 6 inches (15.24 cm).
MCU
68
TMS320F28379S , TMS320F28377S
TMS320F28376S, TMS320F28375S, TMS320F28374S
SPRS881C –AUGUST 2014–REVISED MAY 2016 www.ti.com
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Specifications Copyright © 2014–2016, Texas Instruments Incorporated
5.7.5 Emulation/JTAG
The JTAG port has five dedicated pins: TRST, TMS, TDI, TDO, and TCK. The TRST signal should always
be pulled down through a 2.2-kΩ pulldown resistor on the board. This MCU does not support the EMU0
and EMU1 signals that are present on 14-pin and 20-pin emulation headers. These signals should always
be pulled up at the emulation header through a pair of board pullup resistors ranging from 2.2 kΩ to
4.7 kΩ (depending on the drive strength of the debugger ports). Typically, a 2.2-kΩ value is used.
See Figure 5-9 to see how the 14-pin JTAG header connects to the MCU’s JTAG port signals. Figure 5-10
shows how to connect to the 20-pin header. The 20-pin JTAG header terminals EMU2, EMU3, and EMU4
are not used and should be grounded.
The PD (Power Detect) terminal of the emulator header should be connected to the board 3.3-V supply.
Header GND terminals should be connected to board ground. TDIS (Cable Disconnect Sense) should also
be connected to board ground. The JTAG clock should be looped from the header TCK output terminal
back to the RTCK input terminal of the header (to sense clock continuity by the emulator). Header terminal
RESET is an open-drain output from the emulator header that enables board components to be reset
through emulator commands (available only through the 20-pin header).
Typically, no buffers are needed on the JTAG signals when the distance between the MCU target and the
JTAG header is smaller than 6 inches (15.24 cm), and no other devices are present on the JTAG chain.
Otherwise, each signal should be buffered. Additionally, for most emulator operations at 10 MHz, no
series resistors are needed on the JTAG signals. However, if high emulation speeds are expected
(35 MHz or so), 22-Ω resistors should be placed in series on each JTAG signal.
See the XDS Target Connection Guide for more information about JTAG emulation.
Figure 5-9. Connecting to the 14-Pin JTAG Header