The AM62x Low-Power SK EVM board includes XDS110 class on board
emulation. The connection for the emulator uses an USB 2.0 micro-B connector and the
circuit acts as a Bus powered USB device. The VBUS power from the connector will be used
to power the emulation circuit such that connection to the emulator is not lost when the
power to the SKEVM is removed. Voltage translation buffers are used to isolate the
XDS110 circuit from the rest of the SKEVM. Optionally, JTAG Interface on SKEVM is also
provided through 20 Pin Standard JTAG cTI Header J19. This allows the user to connect an
external JTAG Emulator Cable. Voltage translation buffers are used to isolate the JTAG
signals from cTI header from the rest of the SKEVM. The output from the voltage
translators from XDS110 Section and cTI Header Section are muxed and connected to AM62X
JTAG Interface. If a connection to the cTI 20 Pin JTAG connector is sensed using a
presence detect circuit, the mux will be set to route the 20 pin signals from the cTI
connector to the AM62X SoC in place of the on-board emulation circuit.
The pin-out of the cTI 20 pin
JTAG connector are given in Table 3-6. A ESD protection part number TPD4E004 is provided on USB signals to steer ESD
current pulses to VCC or GND. TPD4E004 protects against ESD pulses up to ±15-kV
Human-Body Model (HBM) as specified in IEC 61000-4-2 and provides ±8-kV contact
discharge and ±12- kV air-gap discharge.
Table 3-6 JTAG Connector (J19)
Pinout
Pin No. |
Signal |
1 |
JTAG_TMS |
2 |
JTAG_TRST# |
3 |
JTAG_TDI |
4 |
JTAG_TDIS |
5 |
VCC3V3_SYS |
6 |
NC |
7 |
JTAG_TDO |
8 |
SEL_XDS110_INV |
9 |
JTAG_cTI_RTCK |
10 |
DGND |
11 |
JTAG_cTI_TCK |
12 |
DGND |
13 |
JTAG_EMU0 |
14 |
JTAG_EMU1 |
15 |
JTAG_EMU_RSTn |
16 |
DGND |
17 |
NC |
18 |
NC |
19 |
NC |
20 |
DGND |
The pin-outs of the cTI 20 pin
JTAG connector are given in the table above. A ESD protection part number TPD4E004
is provided on USB signals to steer ESD current pulses to VCC or GND. TPD4E004
protects against ESD pulses up to ±15-kV Human-Body Model (HBM) as specified in IEC
61000-4-2 and provides ±8-kV contact discharge and ±12- kV air-gap
discharge.