MSP430x31x

MIXED SIGNAL MICROCONTROLLERS

SLAS165D – FEBRUARY 1998 – REVISED APRIL 2000

23

POST OFFICE BOX 655303

TYPICAL CHARACTERISTICS

JTAG fuse check mode

MSP430 devices that have the fuse on the TDI/VPP terminal have a fuse check mode that tests the continuity

of the fuse the first time the JTAG port is accessed after a power-on reset (POR). When activated, a fuse check

Care must be taken to avoid accidentally activating the fuse check mode and increasing overall system power

consumption.

Activation of the fuse check mode occurs with the first negative edge on the TMS pin, after power up, or if the

TMS is being held low after power-up. The second positive edge on the TMS pin deactivates the fuse check

mode. After deactivation, the fuse check mode remains inactive until another POR occurs. After each POR the

fuse check mode has the potential to be activated.

Time TMS Goes Low After POR

TMS

ITF

ITDI

Figure 6. Fuse Check Mode Current, MSP430P/E313,P/E315,C31x

Care must be taken to avoid accidentally activating the fuse check mode, including guarding against EMI/ESD

spikes that could cause signal edges on the TMS pin.

Configuration of TMS, TCK, TDI/VPP and TDO/TDI pins in applications.

C3xx

P/E3xx

TDI

Open

68k, pulldown

TDO

Open

68k, pulldown

TMS

Open

Open

TCK

Open

Open