SLAU278AH May 2009 – March 2021
MSP-FET430PIF, MSP-FET430UIF, MSP-GANG, MSP-GANG430, MSP-PRGS430
With the proper connections, the debugger and an FET hardware JTAG interface (such as the MSP-FET430PIF and MSP-FET430UIF) can be used to program and debug code on the target board. In addition, the connections also support the MSP-GANG430 or MSP-PRGS430 production programmers, thus providing an easy way to program prototype boards, if desired.
Figure 3-1 shows the connections between the 14-pin FET interface module connector and the target device required to support in-system programming and debugging for 4-wire JTAG communication. Figure 3-2 shows the connections for 2-wire JTAG mode (Spy-Bi-Wire). The 4-wire JTAG mode is supported on most MSP430 devices, except devices with low pin counts (for example, MSP430G2230). The 2-wire JTAG mode is available on selected devices only. See the Code Composer Studio IDE for MSP430 MCUs User's Guide or IAR Embedded Workbench IDE for MSP430 MCUs User's Guide for information on which interface method can be used on which device.
The connections for the FET interface module and the MSP-GANG, MSP-GANG430, or MSP-PRGS430 are identical. Both the FET interface module and MSP-GANG430 can supply VCC to the target board (through pin 2). In addition, the FET interface module, MSP-GANG, and MSP-GANG430 have a VCC-sense feature that, if used, requires an alternate connection (pin 4 instead of pin 2). The VCC-sense feature senses the local VCC present on the target board (that is, a battery or other local power supply) and adjusts the output signals accordingly. If the target board is to be powered by a local VCC, then the connection to pin 4 on the JTAG should be made, and not the connection to pin 2. This uses the VCC-sense feature and prevents any contention that might occur if the local on-board VCC were connected to the VCC supplied from the FET interface module, MSP-GANG or the MSP-GANG430. If the VCC-sense feature is not necessary (that is, if the target board is to be powered from the FET interface module, MSP-GANG, or MSP-GANG430), the VCC connection is made to pin 2 on the JTAG header, and no connection is made to pin 4. Figure 3-1 and Figure 3-2 show a jumper block that supports both scenarios of supplying VCC to the target board. If this flexibility is not required, the desired VCC connections may be hard-wired to eliminate the jumper block. Pins 2 and 4 must not be connected at the same time.
The connection to the JTAG connector RST pin of Figure 3-1 is required when programming or debugging a device that supports 2-wire JTAG communication, even when using 4-wire JTAG communication mode on these devices. However, this connection is optional on devices that do not support 2-wire JTAG communication. The MSP430 development tools and device programmers perform a target reset by issuing a JTAG command to gain control over the device. However, if this is unsuccessful, the RST signal of the JTAG connector may be used by the development tool or device programmer as an additional way to assert a device reset.