Multiple adc channel interrupt problem, LPC1768

[Alexshea]

Hello everyone, I used to read temperatures of two LM35 sensors using adc. I used two channels and interrupt too. My code works fine when I read two channels and I want to add two more sensors and read temperatures of 4 LM35 sensors, however when I add channels in adc interrupt my code locks when adc read function is called. For example my adc channel 0 and channel 1 are active when I add if(ADC_ChannelGetStatus(LPC_ADC,ADC_CHANNEL_2,ADC_DATA_DONE)==0) in interrupt when adc_read() function is called the code stops and in debugger it stops moving forward and executing other lines of the code. I added my code and I hope I managed to explain my problem well enough. My chip is LPC1768.

Thanks in advance,

Alex

[Alexshea]

@xiangjun_rong It seems like the code is stuck in adc interrupt when I have more than 2 channels

[Alexshea]

@xiangjun_rong What do you think? I remember once I had one adc and when I wanted to add another one had a similar problem and you helped me. Thought, I won't have any similar problem, since if it works with 2 channels, should work with 3 or more channels as well

[xiangjun_rong]

Hi,

I will answer you at the end of the week, today, I am a bit busy.

BR

XiangJun Rong

[Alexshea]

@xiangjun_rong Hi, it's already Saturday! I was wondering if you check my code today or maybe tomorrow and by the way I need to work with all the 8 adc channels already not with 4 channels. Now I can work with 2 adcs and can't read other channels in adc interrupt

[xiangjun_rong]

Hi, Alex,

I do not use the Keil, I have checked the LPCOpen package, it appears that you do not use the lpcOpen package api function.

Because the conversion time is not a problem, you can use the polling mode as the following code. I suggest you disable all channel interrupt

I do not compile the code, pls have a try yourself.

BR

XiangJun Rong

//disable all channel interrupt

void HW_Init()
{
PINSEL_CFG_Type adcpinsel;
PINSEL_CFG_Type uartPinSel;
UART_CFG_Type uartConfig;

NVIC_SetPriorityGrouping(0x07);

adcpinsel.Funcnum=PINSEL_FUNC_1;
adcpinsel.OpenDrain=PINSEL_PINMODE_NORMAL;
adcpinsel.Pinmode=PINSEL_PINMODE_TRISTATE;
adcpinsel.Pinnum=24;
adcpinsel.Portnum=0;

PINSEL_ConfigPin(&adcpinsel);
adcpinsel.Pinnum=23;
PINSEL_ConfigPin(&adcpinsel);
adcpinsel.Pinnum=25;
PINSEL_ConfigPin(&adcpinsel);
//adcpinsel.Pinnum=26;
//PINSEL_ConfigPin(&adcpinsel);

ADC_Init(LPC_ADC,200000);

ADC_IntConfig(LPC_ADC,ADC_ADINTEN1,DISABLE);
ADC_IntConfig(LPC_ADC,ADC_ADINTEN0,DISABLE);
ADC_IntConfig(LPC_ADC,ADC_ADINTEN2,DISABLE);
ADC_IntConfig(LPC_ADC,ADC_ADINTEN3,DISABLE);
ADC_IntConfig(LPC_ADC,ADC_ADINTEN4,DISABLE);
ADC_IntConfig(LPC_ADC,ADC_ADINTEN5,DISABLE);
ADC_IntConfig(LPC_ADC,ADC_ADINTEN6,DISABLE);
ADC_IntConfig(LPC_ADC,ADC_ADINTEN7,DISABLE);
//ADC_ChannelCmd(LPC_ADC,ADC_CHANNEL_1,ENABLE);
//ADC_ChannelCmd(LPC_ADC,ADC_CHANNEL_0,ENABLE);
//ADC_ChannelCmd(LPC_ADC,ADC_CHANNEL_2,ENABLE);
//ADC_ChannelCmd(LPC_ADC,ADC_CHANNEL_3,ENABLE);

//NVIC_SetPriority(ADC_IRQn,NVIC_EncodePriority(0x07,0,1));
//NVIC_EnableIRQ(ADC_IRQn);

............

}

uint16_t HW_ADC_Read(uint8_t channel_num)
{
uint16_t voltage;
//disable all channels
ADC_ChannelCmd(LPC_ADC,ADC_CHANNEL_0,DISABLE);
ADC_ChannelCmd(LPC_ADC,ADC_CHANNEL_1,DISABLE);
ADC_ChannelCmd(LPC_ADC,ADC_CHANNEL_2,DISABLE);
ADC_ChannelCmd(LPC_ADC,ADC_CHANNEL_3,DISABLE);
ADC_ChannelCmd(LPC_ADC,ADC_CHANNEL_4,DISABLE);
ADC_ChannelCmd(LPC_ADC,ADC_CHANNEL_5,DISABLE);
ADC_ChannelCmd(LPC_ADC,ADC_CHANNEL_6,DISABLE);
ADC_ChannelCmd(LPC_ADC,ADC_CHANNEL_7,DISABLE);
//enable the sampled channel
ADC_ChannelCmd(LPC_ADC,1<<channel_num,ENABLE);
ADC_StartCmd(LPC_ADC,ADC_START_NOW);
while(ADC_ChannelGetStatus(LPC_ADC,1<<channel_num,ADC_DATA_DONE)==0) {}
voltage=ADC_ChannelGetData(LPC_ADC,1<<channel_num);
return voltage;
}

[Alexshea]

@xiangjun_rong  Hi, I tried what you recommended now it works with 3 channels only. The moment I add adc0[3] the previous problem appears.It seems like the code is stuck at while(ADC_ChannelGetStatus(LPC_ADC,1<<channel_num,ADC_DATA_DONE)==0) {}. I've also noticed that the problem is with ADC0[3] and not the number of channels, since when I use this channel only the code gets stuck, whereas when channels 0,1,2 can work together without any problem when channel 3 isn't enabled.  I made the changes and added my code here again. I was wondering if you help me solve this problem

[Alexshea]

Hi, thank you very much for your recommendation. I'll try what you said and compile the code. Hope it helps. Interesting, haven't heard anything about lpcopen

[Alexshea]

Awesome! thank you so much. I'll wait for your answer