SLAU320AJ July 2010 – May 2021
Reference function: SetInstrFetch
Sometimes it is useful for the target device to directly execute an instruction presented by a host over the JTAG port. To accomplish this, the CPU must be set to the instruction-fetch state. With this setting, the target device CPU loads and executes an instruction as it would in normal operation, except that the instruction is transmitted through JTAG. Bit 7 of the JTAG control signal register indicates that the CPU is in the instruction-fetch state. TCLK should be toggled while this bit is zero. After a maximum of seven TCLK clocks, the CPU should be in the instruction-fetch mode. If not (bit 7 = 1), a JTAG access error has occurred and a JTAG reset is recommended.
IR_SHIFT("IR_CNTRL_SIG_CAPTURE") | ||
DR_SHIFT16(0x0000) = Readout data | ||
Bit 7 of TDOvalue = 0? | ||
ClrTCLK | ||
SetTCLK | ||
CPU is in the instruction-fetch state |