Debug Test Access Port
ARM DDI 0301H Copyright © 2004-2009 ARM Limited. All rights reserved. 14-39
ID012310 Non-Confidential, Unrestricted Access
14.8.18 Reading coprocessor registers
1. Load the value into ARM register R0:
ITRSEL ; select the ITR and EXTEST
INST MRC px,y,R0,ca,cb,z
RTI
LOOP
INST 0x00000000 Ready
UNTIL Ready==1 ; wait until instruction ends
2. Use the standard sequence that Reading a current mode ARM register in the range R0-R14
on page 14-34 describes.
14.8.19 Writing coprocessor registers
1. Write the value onto R0, using the standard sequence. See Writing a current mode ARM
register in the range R0-R14 on page 14-34 for more details. Scan chain 5 and EXTEST
are selected.
2. Transfer the contents of R0 to a coprocessor register:
ITRSEL ; select the ITR and EXTEST
INST MCR px,y,R0,ca,cb,z
RTI
LOOP
INST 0x00000000 Ready
UNTIL Ready==1 ; wait until instruction ends