TMS320F28374S: continuous sampling for an ADC

liusuhefeng feng

Tool/software:

Hello,

I want to configure continuous sampling conversion without triggering an interrupt

The configuration in the data sheet seems to use interrupt to generate trigger signals(ADCINT1) that convert the ADC,

Is there any related configuration example for reference?

（If there is no direct method, the alternative is to configure a high-frequency PWM assisted trigger ADC）

Thanks.

over 1 year ago

0 Joseph Casuga over 1 year ago

TI__Mastermind 41690 points

Hi Liusuhefeng,

Yes, this is possible. How this works is that the initial conversion is triggered by software on the first 8 SOCs. The last two SOCs will trigger ADC interrupts which will then trigger the conversion of the other 8 SOCs. Conversion will then occur continuously after that. Please see example adc_ex5_soc_continuous.

Regards,

Joseph

0 liusuhefeng feng over 1 year ago in reply to Joseph Casuga

Prodigy 30 points

HI Joseph,

Thanks for your reply!

I see this example where an ADC interrupt is triggered by an SOC and multiple SOCs are used to achieve continuous sampling with one interrupt triggering multiple samples. Does this mean that the sampling frequency is 8 times higher than the interrupt frequency?

In my project, adc interrupt is triggered by PWM and at a fixed frequency, and part of the SOC is used to convert other channels, I wonder if it is possible to achieve continuous sampling with only a small amount of SOC?

Regards

+1 Joseph Casuga over 1 year ago in reply to liusuhefeng feng

TI__Mastermind 41690 points

Hi Liusuhefeng,

With the continuous sampling, one SOC is always converting and the rate of sampling is not dictated by interrupt frequency since the SOCS are converting in round robin mode continuously. Here, the interrupts are just used as flags to denote that a group of SOCs has completed converting and other interrupts would start the conversion of the other half of the SOC. It is like a ping-pong method that starts with one software ADC trigger and conversion continues from that point on. With this method, you will get the maximum throughput of the ADC which is specified in the datasheet.

Using smaller group of SOCs using this technique will still give you the maximum ADC throughput since there is no stopping of conversions onse the SW trigger is issued, unless all the 4 ADC interrupts are disabled.