PXD20RM Datasheet, PDF (639/1628 Pages) Freescale Semiconductor, Inc – PXD20 Microcontroller

Chapter 16
Enhanced Direct Memory Access (eDMA)
16.1 Introduction
The DMA (Direct Memory Access) is a second-generation platform module capable of performing
complex data transfers with minimal intervention from a host processor via 16 programmable channels.
Intended for use as part of the Standard Product Platform (SPP), the hardware microarchitecture includes
a DMA engine which performs source and destination address calculations, and the actual data movement
operations, along with a local memory containing the transfer control descriptors (TCD) for the channels.
This SRAM-based implementation is used to minimize the overall module size.
Figure 16-1 is a block diagram of the DMA module.
DMA
DMA engine
hrdata[{63,31}:0]
data_path
SRAM
Transfer
Control
Descriptor (TCD)
64
pmodel_charb
addr_path
c
o
n
t
r
o
l
addr
wdata[31:0]
0
j
j+1
n-1
rdata[31:0]
IPS
Bus
AMBA
AHB
Bus
hwdata[{63,31}:0]
haddr[31:0]
ipd_req[n-1:0]
Figure 16-1. DMA block diagram
dma_ipi_int[n-1:0]
dma_ipd_done[n-1:0]
Freescale Semiconductor
PXD20 Microcontroller Reference Manual, Rev. 1
Preliminary—Subject to Change Without Notice
16-1