Ameba-D User Manual
User Manual All information provided in this document is subject to legal disclaimers. © REALTEK 2019. All rights reserved.
92
Handshaking interface supports single or burst DMA transactions
Polarity control for hardware handshaking interface
Enabling and disabling of individual DMA handshaking interfaces
9.1.3.6
Flow Control
Programmable flow control at block transfer level (source, destination, or DMAC)
Softwarecontrolofsourcedatapre-fetchwhendestinationisflowcontroller
9.1.3.7
Interrupts
Combined and separate interrupt requests
Interrupt generation on:
DMA transfer (multi-block) completion
Block transfer completion
Single and burst transaction completion
Error condition
Support of interrupt enabling and masking
9.2
Functional Description
This chapter describes the functional details of the DMAC component. There is an option to configure AHB Lite, which is the implementation of
AMBA 2.0 AHB-Lite. The AHB Lite configuration does not include the following:
Requesting/granting protocols to the arbiter and split/retry responses from the slaves; all slaves are made non-split capable
No arbiter as the signals associated with the component are not used: hbusreq and hgrant
No write data, address, or control multiplexers
Pause mode not enabled
Default master number changed to1
Number of masters is changed to1
9.2.1
Setup/Operation of DMA Transfers
“Programming a Channel” describes how to program the DMAC in order to perform DMA transfers. This section discusses how a single block
transfer, made up of transactions, is actually performed. The relevant settings of the DMAC are also discussed here.
9.2.2
Block Flow Controller and Transfer Type
The device that controls the length of a block is known as the flow controller. Either the DMAC, the source peripheral, or the destination
peripheral must be assigned as the flow controller.
If the block size is known prior to when the channel is enabled, then the DMAC should be programmed as the flow controller. The block
size should be programmed into the CTLx.BLOCK_TS field.
If the block size is unknown when the DMAC channel is enabled, either the source or destination peripheral must be the flow controller.
The CTL
x
.TT_FC field indicates the transfer type and flow controller for that channel. Table 9-1 lists valid transfer types and flow controller
combinations.
Table 9-1 Transfer types and flow control combinations
Transfer Type
Flow Controller
Memory to Memory
DMAC
Memory to Peripheral
DMAC
Memory to Peripheral
Peripheral
Peripheral to Memory
DMAC
Peripheral to Memory
Peripheral
Peripheral to Peripheral
DMAC
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