Datasheet

Connectors

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2.2.1 20-Pin ARM JTAG Header

In addition to on board XDS100V2 JTAG, one 20-pin ARM JTAG header is added for using external

emulator. This is the standard interface used by JTAG emulators to interface to ARM microcontrollers. The

pinout for the connector is shown in Table 2-2.

Table 2-2. 20-Pin ARM JTAG Header

Signal Name Pin Number Pin Number Signal Name

Vref 1 2 V

nTRST 3 4 GND

TDI 5 6 GND

TMS 7 8 GND

TCK 9 10 GND

RTCK 11 12 GND

TDO 13 14 GND

nRST 15 16 GND

NC 17 18 GND

NC 19 20 GND

2.2.2 Ethernet Interface

The TMS570LS1227 integrates an MII/RMII Ethernet MAC on chip. This interface is routed to the on

board PHY via CBT switches. The board uses a DP83640 PHY. The interface is isolated and brought out

to a RJ-45 connector with integrated magnetics, J1. The pinmux control DIP S2 is used to control the CBT

FET switch for RMII, MII or other functions.

The J1 connector is used to provide a 10/100 Mbps Ethernet interface. This is a standard RJ-45

connector. The cable end pinout for the J1 connector is shown in Table 2-3.

Table 2-3. J1, Ethernet Interface

Pin Number Signal Pin Number Signal

1 D0+ 2 D0-

3 D1- 4 D2+

5 D2- 6 D1-

7 D3+ 8 D3-

Two LEDs are embedded into the connector to report link status (green LED) and transmit and receive

status of the PHY (yellow LED).

2.2.3 CAN Interface

The TMS570LS1227 has up to three DCAN interfaces that provide a high-speed serial interface. Two 3-

pin screw terminal blocks, J2, J3, are used to interface to the DCAN bus. The pinouts for this connector

are shown in Figure 2-3. H means CAN High (CAN H), and L means CAN Low (CAN L).

CAN Bus termination is used to minimize signal reflection on the bus. ISO-11898 requires that the CAN

bus have a nominal characteristic line impedance of 120 Ω. Therefore, the typical terminating resistor

value for each end of the bus is 120 Ω. A split termination method is used to help increase EMC

performance. Split termination is a concept that is growing in popularity because emission reduction can

be achieved very easily. Split termination is a modified standard termination in which the single 120 Ω

resistor on each end of the bus is split into two 60 Ω resistors, with a bypass capacitor tied between the

resistors and to ground. The two resistors should match as close as possible.

Physical Description SPNU568A–September 2012–Revised September 2013

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