7.7.3. Encoding of the timestamp value

Bit 28 of the ETMCCER specifies the encoding of the timestamp value in the timestamp packet. See Configuration Code Extension Register, ETMCCER, ETMv3.1 and later

If the ETM outputs the timestamp values as a Gray-coded number, the number is calculated from the natural binary number using the following equation, where Gray[n] is the nth bit of the resultant Gray code, and binary[n] is the nth bit of the binary number:

      Gray[n] = binary[n] XOR binary[n+1]

The debugger generates the binary number from the traced Gray code using the following equation:

      binary[n] = XOR(Gray[N:n]).

In this equation, N+1 is the size in bits of the timestamp.

Copyright © 1999-2002, 2004-2009, 2011 ARM Limited. All rights reserved.ARM IHI 0014Q
Non-ConfidentialID101211