Read/Write Access Control/Status (Rwcs) Register - STMicroelectronics SPC572L series Reference Manual

e200z215An3 Nexus 3 Module
66.4.13

Read/Write Access Control/Status (RWCS) register

The Read Write Access Control/Status Register provides control for Read/Write Access.
Read/Write access provides DMA-like access to memory-mapped resources on the AHB
System bus either while the processor is halted, or during runtime. Control is provided over
access type, size, count, and certain bus attributes. Note that the internal CPU interfaces to
the caches and local memory are not accessible or utilized by this mechanism. Since the
external interface is used, base address port settings are used to access local memory, and
not the settings of local memory control register base address values. The RWCS Register
also provides Read/Write Access Status information per
SZ MAP
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10
Figure 1154. Read/Write Access Control/Status (RWCS) register
1. ERR and DV are read-only
Bits Name
RWCS[31] AC
RWCS[30] RW
RWCS[29:27] SZ
RWCS[26:24] MAP
(1)
RWCS[23:22] PR
RWCS[21:18] ATTR
RWCS[17:16] —
1940/2058
PR ATTR
Nexus Reg# 0x7; Read/Write
Table 1093. RWCS field descriptions
Access Control
0 End access/ Access has completed
1 Start access
Read/Write Select
0 Read access
1 Write access
Word Size
000 8-bit (byte)
001 16-bit (half-word)
010 32-bit (word)
011 64-bit (doubleword, requires two passes through RWD)
1xx Reserved (default to word)
MAP Select
000 Primary memory map
All other values are reserved
Read/Write Access Priority
00 Reserved (default to highest priority)
01 Reserved (default to highest priority)
10 Reserved (default to highest priority)
11 Highest access priority
Access Attributes
0xxx Reserved
1xxx Reserved
x0xx p_d_hprot[4] driven to 0 for accesses
x1xx p_d_hprot[4] driven to 1 for accesses
xx0x p_d_hprot[3] driven to 0 for accesses
xx1x p_d_hprot[3] driven to 1 for accesses
xxx0 p_d_hprot[2] driven to 0 for accesses
xxx1 p_d_hprot[2] driven to 1 for accesses
Reserved for future functionality
DocID027809 Rev 4
Table
0
(1)
; Reset: 0x0
Description
1094.
CNT
9 8 7 6 5 4 3
RM0400
2 1 0