Table 3-109 Dma Channel Number Register Bit Functions; Table 3-110 Results Of Access To The Dma Channel Number Register; Figure 3-61 Dma Channel Number Register Format - ARM ARM1176JZF-S Technical Reference Manual

3.2.35 c11, DMA Channel Number Register
U1 and
U0 bits
Both 0
Either or both 1
ARM DDI 0301H
ID012310
You can access the DMA channel Number Register, see c11, DMA Channel Number Register,
in User mode when the U bit for any channel is 1.
The contents of these registers must be preserved on a task switch if the registers are
User-accessible.
If the U bit for the currently selected channel is set to 0, and a User process attempts to access
any of these registers the processor takes an Undefined instruction trap.
The purpose of the DMA Channel Number Register is to select a DMA channel.
Table 3-109 lists the purposes of the individual bits in the DMA Channel Number Register.
The DMA Channel Number Register is:
• in CP15 c11
• a 32-bit read/write register common to Secure and Non-secure worlds
• accessible in user and privileged modes.
Figure 3-61 shows the bit arrangement for the DMA Channel Number Register.
31
Table 3-109 lists how the bit values correspond with the DMA Channel Number Register.
Access in the Non-secure world depends on the DMA bit, see c1, Non-Secure Access Control
Register on page 3-55. The processor can access this register in User mode if the U bit, see c11,
DMA User Accessibility Register on page 3-107, for any channel is set to 1. Table 3-110 lists the
results of attempted access for each mode.

Table 3-110 Results of access to the DMA Channel Number Register

Secure
DMA
Privileged
bit
Read or Write
0 Data
1 Data
0 Data
1 Data
Copyright © 2004-2009 ARM Limited. All rights reserved.
Non-Confidential, Unrestricted Access
SBZ/UNP

Figure 3-61 DMA Channel Number Register format

Table 3-109 DMA Channel Number Register bit functions

Bits Field name Function
[31:1] - UNP/SBZ.
[0] CN Indicates DMA Channel selected:
0 = DMA Channel 0 selected, reset value
1 = DMA Channel 1 selected.
Non-secure
Secure User
Privileged
Read or Write
Read or Write
Undefined exception Undefined exception
Data Undefined exception
Undefined exception Data
Data Data
System Control Coprocessor
1 0
C
N
Non-secure
User
Read or Write
Undefined exception
Undefined exception
Undefined exception
Data
3-109