ADC with GPDMA

lpcware — Wed, 15 Jun 2016 17:34:39 GMT

Content originally posted in LPCWare by ojima on Tue Jan 10 23:25:10 MST 2012
Hello,

I'm trying to get ADC value continuity with IAR KickStart Kit for LPC1788.

I'm using GPDMA to store ADC values to SRAM.

I expect a behavior of ADC and GPDMA as follows,
                       ____                  ____
ADC DONE(AD0GDR) ___|   |_________________|   |__________________
                           ____                  ____
DMA Transfer      _______|   |_________________|   |__________________
(burst size)

But, an actually behavior is as follows that is guessed by a result.

                       ____                  ____
ADC DONE(AD0GDR) ___|   |_________________|   |__________________
                           _________________________________________
DMA Transfer      _______|
(burst size)

Please help me.

source code(using CMSIS library "lpc177x.lpc178x.cmsis_.driver.library.zip")

[ADC setting]
// Set the P0.13 pin as an analog input.
PINSEL_ConfigPin(0, 13, 3);
PINSEL_SetInBufMode(0, 13, DISABLE);

// Set the ADC sampling rate
ADC_Init(LPC_ADC, 400000);

// Disable　interruption
ADC_IntConfig(LPC_ADC, ADC_ADINTEN7, DISABLE);
// CH#7 enable
ADC_ChannelCmd(LPC_ADC, ADC_CHANNEL_7, ENABLE);
// Enable　interruption
ADC_IntConfig(LPC_ADC, ADC_ADINTEN7, ENABLE);
// Disable NIVC interruption
NVIC_DisableIRQ(ADC_IRQn);

[Start sampling]
// channel 1
GPDMACfg.ChannelNum = 1;
// Source memory - unused
GPDMACfg.SrcMemAddr = 0;
// Destination memory
GPDMACfg.DstMemAddr = (uint32_t) s_dataBuf;
// Transfer size
GPDMACfg.TransferSize = 1000;
// Transfer width - unused
GPDMACfg.TransferWidth = 0;
// Transfer type
GPDMACfg.TransferType = GPDMA_TRANSFERTYPE_P2M;
// Source connection
GPDMACfg.SrcConn = GPDMA_CONN_ADC;
// Destination connection - unused
GPDMACfg.DstConn = 0;
// Linker List Item - unused
GPDMACfg.DMALLI = 0;
GPDMA_Setup(&GPDMACfg);

// Enable GPDMA channel 1
GPDMA_ChannelCmd(1, ENABLE);

// Start ADC
ADC_BurstCmd(LPC_ADC, ENABLE);

[results]
s_dataBuf[0] 0xC7007850
s_dataBuf[1] 0x07007850
      :
s_dataBuf[15] 0x07003C20
s_dataBuf[16] 0x77007840
      :

Re: ADC with GPDMA

lpcware — Wed, 15 Jun 2016 17:34:40 GMT

Content originally posted in LPCWare by ojima on Tue Jan 10 23:28:49 MST 2012
Sorry, There is a typo at result

original
s_dataBuf[0] 0xC7007850
s_dataBuf[1] 0x07007850
:
s_dataBuf[15] 0x07003C20
s_dataBuf[16] 0x77007840
:

fixed
s_dataBuf[0] 0xC7007850
s_dataBuf[1] 0x07007850
:
s_dataBuf[15] 0x07003C20
s_dataBuf[16] 0x87007840
:

OJIMA

Re: ADC with GPDMA

lpcware — Wed, 15 Jun 2016 17:34:40 GMT

Content originally posted in LPCWare by ojima on Wed Jan 11 17:24:13 MST 2012
Sorry, I didn't care delay time for available from post.
So, I did other topic as same thing. That mean I did multipost.
I want to merge this topic to "lpc1788 ADC burst" topic.

I've changed the sample source and got a result I expect.
I will show changing point at "lpc1788 ADC burst" topic.

OJIMA

topic Re: ADC with GPDMA in LPC Microcontrollers

ADC with GPDMA

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Re: ADC with GPDMA