User Manual for J-Link JTAG Isolator 1/4 UM08010-R3 User Manual J-Link JTAG Isolator Introduction The J-Link JTAG Isolator can be connected between J-Link ARM and any ARM- board that uses the standard 20-pin JTAG-ARM connector to provide electrical isolation. This is essential when the development tools are not connected to the same ground as the application. It is also useful to protect the development tools from electrical spikes that often occur in some applications, such as motor control applications. A 20-pin flat cable (supplied with J-Link) is needed to connect the target. Power supply Both sides, target and emulator, are totally isolated and separately powered. The target side draws power from pins 1 or 2, the emulator side draws power from pin 19. Figure 1. J-Link JTAG Isolator Reset LED Emulator Target Side side (J-Link) Power LED Power LED Features 1kV DC isolation 3.3V and 5V target operation supported Powered from emulator and target JTAG standard 20-pin connection supporting TRST, TDI, TMS, TCK, RTCK, TDO and RESET signals Power consumption on target side: < 50mA JTAG frequency: Up to 4MHz 3 LEDs to indicate emulator power, target power and target RESET 2008 SEGGER Microcontroller GmbH & Co. KG TARGET EMULATOR User Manual for J-Link JTAG Isolator 2/4 Connectors and indicators The Isolator uses high speed optocouplers that allow a very low propagation time between input and output. It comes with the following connectors and indicators: 20-pin female EMULATOR connector which can be plugged directly into J- Link 20-pin male TARGET connector for connection of the target cable Green LED indicating power on the emulator side Green LED indicating power on the target side Red LED indicating RESET Block diagram The functional block diagram (Figure 2) illustrates the functional connections between the emulator and target. Figure 2. Functional block diagram POWER POWER GND E GND T RESET RESET GND E TRST TRST GND E TDI TDI GND E TMS TMS GND E TCK TCK GND E RTCK RTCK GND T TDO TDO GND E GND T GND T 2008 SEGGER Microcontroller GmbH & Co. KG