Using the EDMA

8/2/2019 Using the EDMA

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Using the EDMA

IntroductionIn this chapter, you will learn how to program the EDMA to perform a transfer of data from onebuffer to another.

Learning Objectives

EDMA

Goals for Chapter 4

CPUbuf0

Channel

buf1

We will learn how to:Use the EDMA to transfer data from one location to another

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C6000 Integration Workshop - Using the EDMA 4 - 1


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Chip Support Library (CSL)

Chapter Topics

Using the EDMA........................................................................................................................................ 4-1Chip Support Library (CSL) ................................................................................................................... 4-3

Enhanced Direct Memory Access (EDMA)............................................................................................. 4-4Introduction ........................................................................................................................................ 4-4Overview ............................................................................................................................................ 4-5Definitions .......................................................................................................................................... 4-5Example.............................................................................................................................................. 4-6Programming the EDMA (the traditional way) .................................................................................. 4-7

Using CSL............................................................................................................................................... 4-7 Looking more closely at the Config structure?................................................................................... 4-8

EDMA Events Triggering the EDMA................................................................................................... 4-9

Exercise..................................................................................................................................................4-10

Lab 4 Overview...................................................................................................................................4-13

Lab 4 ......................................................................................................................................................4-14DMA (vs. EDMA).............................................................................................................................4-20EDMA: Channel Controller vs. Transfer Controller ........... .......... ........... ........... .......... ............ .......4-22QDMA...............................................................................................................................................4-23DAT (CSL module) ...........................................................................................................................4-24EDMA: Alternate Option Fields.......................................................................................................4-26

4 - 2 C6000 Integration Workshop - Using the EDMA


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Chip Support LibraryC-callable library that supportsprogramming of on-chip peripherals

Supports peripherals in three ways:

1. Resource Management (functions)Verify if periph is availableCheck-out a peripheral

2. Simplifies ConfigurationData structuresConfig functions

3. Macros improve code readability

You still have to know what you wantthe peripherals to do, CSL justsimplifies the code and maintenance

Viterbi Co-Processor VCPeXpansion BusXBUS

Utopia Port (ATM)UTOPIAOn-chip TimersTIMERTurbo Co-Processor TCPPower Down ModesPWRPhase Lock LoopPLLPCI InterfacePCIBuffered Serial PortMcBSP Audio Serial PortMcASP

Hardware InterruptsIRQI2C Bus InterfaceI2CHost Port InterfaceHPIGeneral Purpose Bit I/OGPIO

C64x EMIFsEMIFAEMIFB

External Memory I/FEMIFEnhanced DMA (for 1x dev)EDMADMA (for 0x devices)DMASimple block data moveDATCSL initialization functionCSLSpecifies device typeCHIPCache & internal memoryCache DescriptionCSL Module

The best way to understand CSLis to look at an example...

1. Include Header FilesLibrary and individual module header files

2. Declare HandleFor periphs with multiple resources

3. Define ConfigurationCreate variable of configuration values

4. Open peripheralReserves resource; returns handle

5. Configure peripheralApplies your configuration to peripheral

1. Include Header FilesLibrary and individual module header files

2. Declare HandleFor periphs with multiple resources

3. Define ConfigurationCreate variable of configuration values

4. Open peripheralReserves resource; returns handle

5. Configure peripheralApplies your configuration to peripheral

General Procedure

for using CSL

1. #include < csl.h >#include < csl_timer.h >

2. TIMER_Handle myHandle ;3. TIMER_Config myConfig

myConfig );

= {control, period, counter };

4. myHandle = TIMER_open ( TIMER_DEVANY, ... );5. TIMER_config ( myHandle , &

TimerExample:

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Enhanced Direct Memory Access (EDMA)


IntroductionThe EDMA is a peripheral that can be set up to copy data from one place to another without theCPUs intervention. The EDMA can be setup to copy data or program from a source(external/internal memory, or a serial port) to a destination (e.g. internal memory). After thistransfer completes, the EDMA can autoinitialize itself and perform the same transfer again, orit can be reprogrammed.

How To Move Blocks of Memory?mem2mem1 A0

A1A2A3A4A5

C6000

CPULoadStore

Takes DSP MIPs

Enhanced DMA (EDMA)Direct Memory AccessCan directly access memory

No CPU MIPs

To do its job, what info does the EDMA need?TechnicalTraining

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Overview

EDMA Overview

Source

DestinationTransfer Count

Options

IndexLink AddrCount Reload

31 16 15 0

EDMA requires transfer parametersMost obvious: Src, Dest, Count

Each channel has also has options for:Data sizeChannel PriorityAutoinit (linking)Inc/dec src & dest addresses

Channel 63 (15)

Channel 1

Channel 2

...

Channel 0

EDMA

C64x has 64 channels

C67x has 16 channels

EDMA Channel

How much does the EDMA move?Technical TrainingOrganization

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Definitions

EDMA - How much to move

Element

ESIZE

00: 32-bits01: 16-bits10: 8-bits11: rsvd

ESIZE

Elem 1Elem 2

Elem N

Frame

..

# Elements (N)015

Frame 1Frame 2

Frame M

Block

..

1631

# Frames (M-1)

OptionsSource

DestinationIndex

Link Addr Cnt Reload31 0

Transfer Count



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ExampleHow do we setup the six EDMA parameters registers to transfer 4 byte-wide elements from loc_8to myDest ?

EDMA Example

myDest:

8 bits

89

1011

(Src: loc_8)

8-bit Values1 2 3 4 5 6

7 12

13 14 15 16 17 18

19 20 21 22 23 24

25 26 27 28 29 30

8 9 1 0 118 9 1 0 1189

1011

ESIZE

00: 32-bits01: 16-bits10: 8-bits11: rsvd

OptionsSource

DestinationIndex


Transfer Count

ESIZE10

Goal:

Transfer 4 elementsfrom loc_8 to myDest

# Elements4

0151631

# Frames (less one)0

FS

FS

Frame Sync0: Off1: On

00: fixed (no modification)01: inc by element size10: dec by element size11: index

Addr Update Mode (SUM/DUM)

SUM DUM

How do we program the EDMA?

SUM01

DUM01

FS1

Looking at the EDMA parameters one register at a time:

1. Options :

ESIZE should be self-explanatory based on our previous definitions.

SUM and DUM fields indicate how the source and destination addresses are to bemodified between element reads and writes. Since our example above moves 4consecutive byte elements and writes them to 4 consecutive locations, both SUM andDUM are set to inc by element size . In future chapters, well use other values for them.

Frame Sync (FS) indicates how much data should be moved whenever the EDMA istriggered to run. In our case, since we want to move the whole frame of data when the

CPU starts the EDMA channel, we should set FS = 1. Later, when we use the McBSP,well want to change this value so the EDMA only moves one element per trigger event .

2. Source : Should have the source address of loc_8 .

3. Transfer Counter : Will have the value 4. Actually, it is 0x 0000 0004.

4. Destination : gets the value of myDest .

5. Index : Were not using the index capability in this chapter. We will discuss this in chapter 7.

6. Reload/Linking : Again, this capability is not used in this chapter. Rather we cover it in thenext chapter.



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Using CSL

Programming the EDMA (the traditional way)

Programming the Traditional WayEDMA Reg Values

options 0x51200001source &loc_8count 0x00000004dest &myDestindex 0x00000000rld:lnk 0x00000000

EDMA Reg Valuesoptions 0x51200001source &loc_8count 0x00000004dest &myDestindex 0x00000000rld:lnk 0x00000000

Traditional Way to Setup Peripherals

1. Determine register field values

2. Compute Hex value for register

3. Write hex values to register with C

Is there an easier way to program these registers?

OptionsSource

DestinationIndex


Transfer Count

ESIZE10

# Elements4

0151631

# Frames (less one)0

FS1

SUM01

DUM01

Using CSL

As shown below, we basically want to get the six 32-bit values we calculated for each registerinto the EDMA channel parameter location.

CSL An Easier Way to Program PeripheralsChip Support Library (CSL) consists of:

Data Types Define data structures used by CSL functionsEDMA_HandleEDMA_Config

Functions Used to configure and manage resourcesEDMA_config()EDMA_setChannel()

Macros Improve code readability & decrease errorsEDMA_OPT_RMK()EDMA_SRC_OF()

OptionsSource

DestinationIndex


Transfer Count

ChannelEDMA_Config myConfig = {0x51200001, // options&loc_8, // source0x00000004, // count&myDest, // destination0x00000000, // index0x00000000 // reload:link

};

EDMA_Config myConfig = {0x51200001, // options&loc_8, // source0x00000004, // count&myDest, // destination0x00000000, // index0x00000000 // reload:link

};

EDMA_config()


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Using CSL

Here are the 5 basic steps to accomplishing this using CSL:

EDMA Programming in 5 Easy Steps

2 Declare a handle (will point to an EDMA channel)EDMA_Handle hMyChan;

3 Fill in the config structure (values to program into EDMA)EDMA_Config myConfig = {

EDMA_OPT_RMK(), };

1 Include the necessary header files#include #include

4 Open a channel (requests any avail channel; and reserves it)hMyChan = EDMA_open( EDMA_CHA_ANY, EDMA_OPEN_RESET) ;

5 Configure channel (writes config structure to assigned channel)EDMA_config(hMyChan, &myConfig);


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Looking more closely at the Config structure?

You can see we used CSL macros (_RMK and _OF macros) to create the six 32-bit hex values.The beauty of these macros is how easy they are to read and write. This will come in handy whenwe need to debug our code, or later on when we need to maintain the code.

EDMA Parameter Valuesoptions 0x51200001source &loc_8count 0x00000004dest &myDestindex 0x00000000rldcnt:lnk 0x00000000

EDMA Parameter Valuesoptions 0x51200001source &loc_8count 0x00000004dest &myDestindex 0x00000000rldcnt:lnk 0x00000000

EDMA_Config myConfig = {EDMA_OPT_RMK(

EDMA_OPT_PRI_LOW,EDMA_OPT_ESIZE_8BIT,EDMA_OPT_2DS_NO,EDMA_OPT_SUM_INC,EDMA_OPT_2DD_NO,EDMA_OPT_DUM_INC,

EDMA_OPT_TCINT_YES,EDMA_OPT_TCC_OF(5),EDMA_OPT_LINK_NO,EDMA_OPT_FS_YES),

EDMA_SRC_OF(loc_8),EDMA_CNT_OF(0x00000004),EDMA_DST_OF(myDest),EDMA_IDX_OF(0),EDMA_RLD_OF(0)

};

EDMA_Config myConfig = {EDMA_OPT _RMK(

EDMA_OPT_PRI_LOW,EDMA_OPT_ ESIZE _8BIT,EDMA_OPT_2DS_NO,EDMA_OPT_ SUM _INC,EDMA_OPT_2DD_NO,EDMA_OPT_ DUM _INC,

EDMA_OPT_TCINT_YES,EDMA_OPT_TCC_OF(5),EDMA_OPT_LINK_NO,EDMA_OPT_ FS _YES),

EDMA_SRC _OF ( loc_8 ),EDMA_CNT _OF ( 0x00000004 ),EDMA_DST _OF ( myDest ),EDMA_IDX _OF (0),EDMA_RLD _OF (0)

};

_RMK (register make) createsa single hex value from optionsymbols you select

_OF macro performs anyneeded casting (and providesvisual consistency)

Highlighted in BLUE are theoptions discussed thus far(esize, sum, dum, fs, src, cnt, dst)



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EDMA Events Triggering the EDMA

EDMA Events Triggering the EDMA

EDMA Events

EDMAChannels

2

1

0

EDMA_setChannel( hMyChan )

EDMA Event Input

0

1

0

0

ER

How do you trigger an EDMA channel to run,that is, start copying a block of memory?

Channels must receive a start event in order to runSet an event by writing to the EDMAs Event Register (ER)

Conveniently, a CSL function can set the ER bit for us:

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In Chapter 6 we will show how to use interrupt events to trigger the EDMA. This will come inhandy when we use the McBSP to tell the EDMA when to transfer a value to it, or when to pick

up a value from its receive register.


Documents

Using the EDMA