2.8.7. APB-AP Banked Data Registers, BD0-BD3, 0x10-0x1C

BD0-BD3 provide a mechanism for directly mapping through DAP accesses to APB transfers without having to rewrite the Transfer Address Register within a four word boundary. For example, BD0 reads/write from TAR, and BD1 from TAR+4.

Table 2.32 shows the bit assignments.

Table 2.32. APB-AP Banked Data Registers bit assignments


If DAPADDR[7:4] = 0x0001, so accessing APB-AP registers in the range 0x10-0x1C, then the derived PADDR[31:0] is:

  • Write mode: Data value to write for the current transfer to external address TAR[31:4] + DAPADDR[3:2] + 2'b00.

  • Read mode: Data value read from the current transfer from external address TAR[31:4] + DAPADDR[3:2] + 2'b00.

Auto address incrementing is not performed on DAP accesses to BD0-BD3.

Reset value = 0x00000000

Copyright © 2004-2009 ARM. All rights reserved.ARM DDI 0314H