JTAG programming is through the ETMJTAGPORT described in ETMJTAGPORT. The interface is an extension of the ARM TAP controller, and is assigned scan chain number 6. The scan chain consists of a 40-bit shift register comprising:

Some registers in CoreSight ETM11 are outside the address range of the JTAG interface. These include the CoreSight Management Registers and the CoreSight ETM11 Integration Registers, which are accessible via APB. The CoreSight Management Registers are only used in a CoreSight system. The general arrangement of the ETM JTAG registers is shown in Figure 3.2.

When writing a register, the data to be written is scanned into the 32-bit data field, the address of the register into the 7-bit address field and a 1 into the read/write bit. A register is read by scanning its address into the address field and a 0 into the read/write bit. The 32-bit data field is ignored.

The read data is transferred into the lower 32-bit data field when the TAP state machine transitions through CAPTURE-DR.