MSP430P325A Datasheet, PDF (25/35 Pages) Texas Instruments – MIXED SIGNAL MICROCONTROLLER

MSP430C32x, MSP430P325A
MIXED SIGNAL MICROCONTROLLER
SLAS219B − MARCH 1999 − REVISED MARCH 2000
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
current, I_TF , of 1 mA at 3 V, 2.5 mA at 5 V can flow from the TDI/VPP pin to ground if the fuse is not burned.
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 TMS
is being held low during 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
I_TF
I_TDI
Figure 8. Fuse Check Mode Current, MSP430P/E325A, C32x
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.
TDI
TDO
TMS
TCK
C3xx
Open
Open
Open
Open
P/E3xx
68k, pulldown
68k, pulldown
Open
Open
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