AM335x ADC FIFO size.

uitytur

Prodigy 215 points

hi all~

I Use AM335x CPU.

I Want to change ADC FIFO Size.

Its size is now 0~127(128) .

(AM335x TRM Rev.J 1579 Page. - 12.5.1.57 - 100h FIFO0DATA( or 200h FIFO1DATA))

But I need only 1 FIFO size.

Because I need to read current value.

Is It Possible??

over 12 years ago

0 Biser Gatchev-XID over 12 years ago

TI__Guru**** 393215 points

This is programmed in the FIFO0THRESHOLD and FIFO1THRESHOLD registers. The FIFO in which data will be stored is selected by bit 26 (FIFO_select) in the STEPCONFIGx register.

0 uitytur over 12 years ago in reply to Biser Gatchev-XID

Prodigy 215 points

thanks reply~

refer 12.5.1.52 - (Program the desired FIFO0 data sample level to reach before
generating interrupt to CPU (program to value minus 1))

I want 1 FIFO Size , therefore 1-1 = 0,

Default vale of [5-0] FIFO0_threesold_Level is 0(Zero)

But FIFO Operate size 128..

Is This Register(FIFOxTHRESOLD) for Interrupt generation ?

0 Biser Gatchev-XID over 12 years ago in reply to uitytur

TI__Guru**** 393215 points

Both for interrupt and DMA.

0 uitytur over 12 years ago in reply to Biser Gatchev-XID

Prodigy 215 points

I use polling mode (SW oneshot)

I don't use interrupt and DMA...

can I change FIFO size ?

0 Biser Gatchev-XID over 12 years ago in reply to uitytur

TI__Guru**** 393215 points

You can poll the IRQSTATUS register, no need for real interrupt.

0 Tyler Berryhill over 12 years ago in reply to uitytur

TI__Intellectual 1980 points

The FIFO size is not programmable. However, in addition to Biser's suggestion, you can poll the FIFO0COUNT or FIFO1COUNT register to see that your one result is in the FIFO before reading the FIFO0DATA or FIFO1DATA registers.

-Tyler

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AM335x ADC FIFO size.