Kinetis Microcontrollers中的主题 Re: Need help with configuring eDMA Software TCD for two-level dma transfer

Need help with configuring eDMA Software TCD for two-level dma transfer

wildhorsemusic — Fri, 13 Jan 2017 05:32:43 GMT

Hi Folks, I am building an application that will use the eDMA in the Kinetis K64F MCU. I need help in setting up the eDMA as a two-level dma transfer.

I am just focused on one TCD for the moment (once I understand the configuration case, I can replicate it in other areas of my code).

1) I am transferring 32bits of data per transfer.

2) The transfer will be triggered by a single software trigger by setting the CR.START to true.

3) Here's a list of software and hardware addresses:

OFFSET	SOURCE	DESTINATION	OFFSET
	0x1FFF1480	0x4004A008
0x4	0x1FFF1484	0x4004A00C	0x4
0x4	0x1FFF1488	0x4004B000	0xFF4
0x4	0x1FFF148C	0x4004B004	0x4

*Note: Source & Destination sizes are 4 bytes (32bits)

3) I believe that the entire transfer will have to be done using minor and major loops, along with minor and major channel linking back to itself in order to trigger the channel requests

4) I know that I can do it by breaking it into two transfers, but I'd rather get a two-level configuration working because it will save me some memory on extra swTCD's.

5) Here's what I think the swTCD should look like:

SADDR =     0x1FFF1480
SOFF =     0x4
ATTR =     0x202
NBYTES =     0x8
SLAST =     0x0
DADDR =     0x4004A008
DOFF =     0xFF4
CITER =     0x2
DLAST_SGA = 0x0
CSR =     0x1
BITER =     0x2

DMA_BWR_CR_CLM(DMA_UNIT, true);
DMA_BWR_CR_EMLM(DMA_UNIT,true);

Am I close?

Thank you very much!

Re: Need help with configuring eDMA Software TCD for two-level dma transfer

xiangjun_rong — Mon, 16 Jan 2017 09:37:35 GMT

Hi, Duane,

From your description, it seems that you want to transfer 2 words from the base address 0x1FFF1480 to the destination address 0x4004A008, transfer another two word from base address 0x1FFF1488 to the destination address 0x4004B000. If it is the case, because the destination address is not continuous, as you said that you can use the channel link mode or minor/major loop mode to implement the scheme.

In minor/major loop mode, this is the key register setting:

CR[EMLM] = 1;

DMA_TCDn_NBYTES_MLOFFYES=(1<<30)|(0xff4<<10)|0x02;

SOFF = DOFF= 0x4;

BITER = 0x2

It is okay, pls have a try.

XiangJun Rong

Re: Need help with configuring eDMA Software TCD for two-level dma transfer

wildhorsemusic — Tue, 17 Jan 2017 04:13:51 GMT

Thank you XiangJun Rong,

I will try it shortly and let you know.

So, I thought that I could use the DOFF value to adjust the destination address once for every BITER? The documentation does not give many examples that show how to configure a 2-level transfer with channel linking to trigger the subsequent DMA Requests after the initial Software Trigger. I need to be able to start a whole series of transfers with a single Software Trigger, with Channel Linking and SGA combinations.

Thanks!

Duane

Re: Need help with configuring eDMA Software TCD for two-level dma transfer

wildhorsemusic — Tue, 17 Jan 2017 21:15:52 GMT

XiangJun Rong,

I tried the configuration you recommended. However, I get a DBE (Destination Bus Error) after the 2nd TCD loads (using SGA). The documentation is not very clear on all the causes for getting a Bus Error. The eDMA stops with the SADDR = 1FFF14A0 and the DADDR = 43FE0808. I should have been clear that the destination addresses are peripheral registers and should be written 32bits at a time. The source addresses are memory addresses where the data and software TCDs are stored. I am pasting the software TCD's that I create based upon your earlier configuration suggestion. The only thing different in the TCDs are the minor loop offsets and the addresses.

#1 ga_swtcd_start[0] edma_software_tcd_t {...} 0x1fff1f40
SADDR uint32_t 0x1fff148c
SOFF uint16_t 0x4
ATTR uint16_t 0x0
NBYTES uint32_t 0x403fd002
SLAST uint32_t 0x0
DADDR uint32_t 0x4004a008
DOFF uint16_t 0x4
CITER uint16_t 0x8002
DLAST_SGA uint32_t 0x1fff1f60
CSR uint16_t 0x11
BITER uint16_t 0x8002
#2 ga_swtcd_start[1] edma_software_tcd_t {...} 0x1fff1f60
SADDR uint32_t 0x1fff149c
SOFF uint16_t 0x4
ATTR uint16_t 0x0
NBYTES uint32_t 0x4009f002
SLAST uint32_t 0x0
DADDR uint32_t 0x43fe0808
DOFF uint16_t 0x4
CITER uint16_t 0x8002
DLAST_SGA uint32_t 0x1fff1f80
CSR uint16_t 0x11
BITER uint16_t 0x8002
#3 ga_swtcd_start[2] edma_software_tcd_t {...} 0x1fff1f80
SADDR uint32_t 0x1fff14ac
SOFF uint16_t 0x4
ATTR uint16_t 0x0
NBYTES uint32_t 0x4009f002
SLAST uint32_t 0x0
DADDR uint32_t 0x43fe1000
DOFF uint16_t 0x4
CITER uint16_t 0x8002
DLAST_SGA uint32_t 0x1fff1fa0
CSR uint16_t 0x11
BITER uint16_t 0x8002

My initial configuration was to use a minor loop for the first 2 32bit transfers, then a major loop to offset the destination address for the 2nd set of 32bit transfers, but it doesn't seem to work.

Thanks! Duane

Re: Need help with configuring eDMA Software TCD for two-level dma transfer

wildhorsemusic — Wed, 18 Jan 2017 04:57:21 GMT

XiangJun Rong,

One of the other problems that I keep having is when I write to addresses in the BitBand area. I get a DBE error, no matter what I do. After doing some research, I discovered that the eDMA cannot access the BitBand area. While it is described in the K64 Sub-Family Reference Manual, Rev. 2, January 2014, it is not described in the eDMA section. This is SO FRUSTRATING! I spent, all this time working on a solution to find that the eDMA won't work in this application. This kind of critical information should be highlighted in the key areas that apply.

I will have to find a work around.

Thanks for your time.

Duane

Re: Need help with configuring eDMA Software TCD for two-level dma transfer

xiangjun_rong — Wed, 18 Jan 2017 06:31:57 GMT

Hi, Duane,

You are right, the eDMA can not access the address in the BitBand area.

XiangJun Rong

Re: Need help with configuring eDMA Software TCD for two-level dma transfer

wildhorsemusic — Fri, 20 Jan 2017 07:22:42 GMT

XiangJun Rong,

Can I ask you for assistance on this TCD configuration?

SADDR  0x1fff14bc
SOFF  0x1
ATTR  0x0
NBYTES  0x14
SLAST  0x0
DADDR  0x1fff12c0
DOFF  0x1
CITER  0x1
DLAST_SGA 0x1fff1fa0
CSR  0x13
BITER  0x1

I am trying to transfer 5 DWORDS from one memory location to another. However, I keep getting NCE errors.

I have tried configuring it as ATTR = 0202 with SOFF/DOFF = 4, but I keep getting an NCE.

This is really basic stuff, but I seem to be missing something. By the way what does it mean to have a 0-modulo-address-boundary?

Thanks

Duane