Freescale Semiconductor StarCore SC140 - Manual (Page 145)

EOnCE Register Addressing
SC140 DSP Core Reference Manual 4-35
Accessibility of the registers through JTAG is the same as from software with the following exceptions:
• The ETRSMT register is only readable only using the JTAG port.
• The ERCV registers are only writable using the JTAG port.
• PC_LAST and PC_NEXT can only be read by the JTAG port.
• The CORE_CMD register can only be written by the JTAG port in debug state.