NXP Semiconductors KL25 Series - Page 306

19.31.1 MTB Position Register (MTB_POSITION)
The MTB_POSITION register is the trace write address pointer and wrap bit. This
register can be modified by the explicit programming model writes. It is also
automatically updated by the MTB hardware when trace packets are being recorded.
Address: F000_0000h base + 0h offset = F000_0000h
Bit 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
R
POINTER
W
Reset
x* x* x* x* x* x* x* x* x* x* x* x* x* x* x* x*
Bit
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
R
POINTER
WRAP
0
W
Reset
x* x* x* x* x* x* x* x* x* x* x* x* x* x* 0 0
* Notes:
x = Undefined at reset.•
MTB_POSITION field descriptions
Field Description
31–3
POINTER
Trace Packet Address Pointer
Trace packet address pointer. Because a packet consists of two words, the POINTER field is the address
of the first word of a packet. This field contains bits[31:3] of the RAM address that points to the next
unused memory location for the trace data. This is an empty ascending location and is automatically
updated.
A debug agent can add the value of POINTER to the value of MTB_BASE to obtain the absolute pointer
address as seen on the system AHB bus interface.
NOTE: The size of the RAM is parameterized and the most significant bits of the POINTER field are
RAZ/WI.
POSITION register bits greater than or equal to 15 are RAZ/WI, therefore, the active POINTER field bits
are [11:0].
2
WRAP
This bit is set to 1 automatically when the POINTER value wraps as determined by the
MTB_MASTER[MASK] bit in the MASTER Trace Control Register. A debug agent can use the WRAP bit
to determine whether the trace information above and below the pointer address is valid.
1–0
Reserved
This field is reserved.
This read-only field is reserved and always has the value 0.
Memory Map and Register Definition
KL25 Sub-Family Reference Manual, Rev. 3, September 2012
306 Freescale Semiconductor, Inc.