Datasheet
Table Of Contents
- features
- description
- Available Options
- pin designation
- functional block diagram
- Terminal Functions
- short-form description
- absolute maximum ratings
- recommended operating conditions
- electrical characteristics over recommended operating free-air temperature
- supply current into AVCC + DVCC excluding external
- current consumption of active mode versus system frequency
- current consumption of active mode versus supply voltage
- Schmitt-trigger inputs -- Ports P1 and P2, RST/NMI, JTAG (TCK, TMS, TDI/TCLK, TDO/TDI)
- inputs Px.x, TAx
- leakage current
- outputs -- Ports P1 and P2
- output frequency
- wake-up LPM3
- RAM
- LCD
- USART0
- POR brownout, reset
- SVS (supply voltage supervisor/monitor)
- DCO
- crystal oscillator, LFXT1 oscillator
- SD16, power supply and recommended operating conditions
- SD16, analog input range
- SD16, analog performance (fSD16 = 1MHz, SD16OSRx = 256, SD16REFON = 1)
- SD16, built-in voltage reference
- SD16, built-in reference output buffer
- SD16, external reference input
- flash memory
- JTAG interface
- JTAG fuse
- Application Information
- input/output schematic
- Port P1, P1.0 to P1.1, input/output with Schmitt trigger
- Port P1, P1.2 to P1.7, input/output with Schmitt trigger
- Port P2, P2.0 to P2.1, input/output with Schmitt trigger
- Port P2, P2.2 to P2.5, input/output with Schmitt trigger
- Port P2, unbonded GPIOs P2.6 and P2.7
- JTAG pins (TMS, TCK, TDI/TCLK, TDO/TDI), input/output with Schmitt trigger or output
- JTAG fuse check mode
- input/output schematic
- Data Sheet Revision History
MSP430F42xA
MIXED SIGNAL MICROCONTROLLER
SLAS587 -- FEBRUARY 2008
38
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
APPLICATION INFORMATION
JTAG fuse check mode
MSP430 devices that have the fuse on the TDI/TCLK 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 1.8 mA at 3 V can flow from the TDI/TCLK 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 the
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.
The fuse check current only flows when the fuse check mode is active and the TMS pin is in a low state (see
Figure 14). Therefore, the additional current flow can be prevented by holding the TMS pin high (default
condition).
The JTAG pins are terminated internally, and therefore do not require external termination.
Time TMS Goes Low After POR
TMS
I
TF
I
TDI/TCLK
Figure 14. Fuse Check Mode Current, MSP430F42xA