tms320f28068 JTAG

One thing I find missing from embedded digital design is simplicity. One thing I would like to do is boil a complex design down to some key components. First up is JTAG. This is one way an engineer or technician can interface with a embedded microcontroller, that is already connected to a circuit.

I am focusing on Texas Instruments c28x Piccolo MCUs. All information is from the TI website and relevant datasheets.

Pull up resistor means there is a resistance connected between it and the supply voltage, and pull down resistor means it is connected to ground. They are internal when using JTAG.

/TRST has a 2.2 k Ohm pull down resistance.

On the 2806x device, the JTAG port is reduced to 5 pins (TRST, TCK, TDI, TMS, TDO). TCK, TDI, TMS and TDO pins are also GPIO pins. The TRST signal selects either JTAG or GPIO operating mode for the pins. During emulation/debug, the GPIO function of these pins are not available. If the GPIO38/TCK/XCLKIN pin is used to provide an external clock, an alternate clock source should be used to clock the device during emulation/debug since this pin will be needed for the TCK function.

The headers are JTAG-based emulators - XDS510™ class, XDS560™ emulator, XDS100.

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Electrical Design Engineer, Minneapolis, Minnesota

Page 22, 33, 54, 69, 136 on the tms320f28068 datasheet.