stm32 and external adc

[elec_st]

Posted on January 15, 2016 at 19:19

if i have stm32 at 72mhz

what is the maximum adc chip speed i will use with stm32 at 72mhz ? #drinking-from-a-firehose

[Tesla DeLorean]

Posted on January 15, 2016 at 20:17

The SPI and FSMC interfaces would tend to put an upper limit on it, and what you expect to be able to do with the data.

[elec_st]

Posted on January 24, 2016 at 15:55

thank you i just want to maje low cost oscilloscope

and i want to get the maximum sample rate with stm32 what is the best connection interface type between adc and stm32?

[Tesla DeLorean]

Posted on January 24, 2016 at 17:11

Well IRQ's are going to top out at a few hundred KHz

FSMC Might deliver 9-12 MSps, but you have a very small capture buffer.The DCMI on the F4 might offer 54 MSps.You might be able to get significantly higher rates with CCD/FIFO arrangement to handle the disparity between the high sample rate, and lower/smaller processing rates.

[elec_st]

Posted on January 24, 2016 at 18:34

thank you for helping me . so this is the best connection

[Tesla DeLorean]

Posted on January 24, 2016 at 19:10

There are certainly chips in that domain that can get you to speeds and capacities beyond the performance of the STM32 itself

http://www.glyn.com/data/glyn/media/doc/AVERLOGIC_product_overview_07092010.pdf

You'd have to determine the goals for speed, width, depth and cost.

[elec_st]

Posted on January 29, 2016 at 17:25

the goals for speed

is take afew sample to draw it in lcd

width  

i will use 2 adc 8bit

''16bit''

in

Interleaving ADC

mode to increase speed time

depth 

if you mean the sample recording length  1kbyte is enough

but the problem  know clock source ?  how to get HW clock out  from stm32 and it must change apple 

[Tesla DeLorean]

Posted on January 29, 2016 at 18:00

Had me thinking for a second, changeable...

The integer clocking schemes of the STM32 aren't what I'd call flexible. You can output internal clocks via PA8 (MCO) or from TIMx_CHx pins. With a FIFO you could use totally different clock rates. If you needed a lot of control and NCO or DDS would work. 1KB seems very little data.