Direct Memory Access Controller (DMAC)
User Manual All information provided in this document is subject to legal disclaimers. © REALTEK 2019. All rights reserved.
137
Bit
Name
Access
Reset
Description
63:8+dnc
1
RSVD
N/A
0x0
Reserved
7+dnc
CH_EN_WE
W
0x0
Channel Enable Write Enable.
7:dnc
1, 2
RSVD
N/A
0x0
Reserved
dnc
-1:0
CH_EN
R/W
0x0
Enables/Disables the channel. Setting this bit enables a channel; clearing this bit
disables the channel.
0 = Disable the Channel
1 = Enable the Channel
The ChEnReg.CH_EN bit is automatically cleared by hardware to disable the
channel after the last AMBA transfer of the DMA transfer to the destination has
completed. Software can therefore poll this bit to determine when this channel
is free for a new DMA transfer.
9.3.2.2
Channel Registers
The channel registers consist of the following, where x = 0 to 7:
CFGx – Configuration register for channel
x
CTLx – Control register for channel
x
DARx – Destination address register for channel
x
DSRx – Destination scatter register for channel
x
DSTATx – Destination status register for channel
x
DSTATARx – Destination status address register for channel
x
LLPx – Linked list pointer register for channel
x
SARx – Source address register for channel
x
SGRx – Source gather register for channel
x
SSTATx – Source status register for channel
x
SSTATARx – Source status address register for channel
x
The SARx, DARx, LLPx, CTLx, and CFGx channel registers should be programmed prior to enabling the channel. However, if an LLI update occurs
before commencing data transfer, SARx and DARx may not need to be programmed prior to enabling the channel; refer to rows 6 to 10 in Table 9-
19. It is an Illegal Register Access when a write to the SARx, DARx, LLPx, CTLx, SSTATx, DSTATx, SSTATARx, DSTATARx, SGRx, or DSRx registers
occurs when the channel is enabled.
9.3.2.2.1
SARx
Name:
Source Address Register for Channel x
Size:
64 bits (upper 32 bits are reserved)
Address offset:
for
x
= 0 to 7:
SAR0 – 0x000
SAR1 – 0x058
SAR2 – 0x0b0
SAR3 – 0x108
SAR4 – 0x160
SAR5 – 0x1b8
SAR6 – 0x210
SAR7 – 0x268
Read/write access:
read/write
The starting source address is programmed by software before the DMA channel is enabled, or by an LLI update before the start of the DMA
transfer. While the DMA transfer is in progress, this register is updated to reflect the source address of the current AHB transfer.
Note
: You must program the SAR address to be aligned to CTLx.SRC_TR_WIDTH.
For information on how the SAR
x
is updated at the start of each DMA block for multi-block transfers, refer to
1
dnc = DMAH_NUM_CHANNELS
2
If dnc = 8, then this field is not present.
Realtek confidential files
The document authorized to
SZ99iot
2019-05-15 10:08:03