Spy-Bi-Wire is a serialised
JTAG
JTAG (named after the Joint Test Action Group which codified it) is an industry standard for verifying designs and testing printed circuit boards after manufacture.
JTAG implements standards for on-chip instrumentation in electronic design autom ...
protocol developed by Texas Instruments for their
MSP430
The MSP430 is a mixed-signal microcontroller family from Texas Instruments, first introduced on 14 February 1992. Built around a CPU, the MSP430 is designed for low cost and, specifically, low power consumption embedded applications.
Applica ...
micro controller
A microcontroller (MCU for ''microcontroller unit'', often also MC, UC, or μC) is a small computer on a single VLSI integrated circuit (IC) chip. A microcontroller contains one or more CPUs ( processor cores) along with memory and programmable ...
s.
In this protocol only two connections are used instead of the usual four pins for the general
JTAG
JTAG (named after the Joint Test Action Group which codified it) is an industry standard for verifying designs and testing printed circuit boards after manufacture.
JTAG implements standards for on-chip instrumentation in electronic design autom ...
interface. The two connections are a bidirectional data output, and a clock. The clocking signal is split into a period of three clock pulses, for each clock pulse the TDI, TDO and TMS signals are passed on the micro controller via the bidirectional data output.
References
{{reflist
External links
"MCU debug on a pin-count budget"MSP430™ Programming Via the JTAG Interface
Hardware testing
IEEE standards
Texas Instruments microcontrollers