new to Kinetis

[christopherhuds]

I have been using Symphony DSP's for 10years but now I am having to move to something else due to EOL, so need to do a code port and keep things as much the same as possible. Kinetis K20 looks like its the choice but totally lost as to all the features multiplexed on all the pins etc.

My application uses 4 analog inputs  two running at 64Ksps and other two at 16Ksps all at 16bit resolution.

what I want to know is:

1) I want to use all 4 ADCs_SE, is it possible to do 16bit on all 4 without PGA limitation?

2) can I hardware average, sampling at say 248Ksps and first two get 4x average and other two get 16x average?

3) it is unclear to me which pins to use since all 4 ADC have SE8-18 pins available.  Is this just to give me the option of moving the signal from one pin to another or do all the various pins do something?

4) do I have to hook up SE ADC pins in twos: signal and ground?

5) As for other peripherals, they also have multiple pins, same deal as #3?

6) I plan on using this as the programmer: P&E Microcomputer Systems - USB Multilink Universal FX - USB Multilink Universal FX All-In-One Devel... , what pins are required to hook up to connect the device?

[mjbcswitzerland]

Christopher

The K20 has 2 ADCs (each has two channels that can be sampled in series when working in HW triggered mode). This gives 4 channels if you don't need 4 samples in parallel. Some Kinetis devices has 4 ADC independent ADC converters (ag. K60, K61, K70)

1. All ADCs can be set to 16 bit mode but the actual resolution obtained depends on settings and averaging. The max. achievable is around 14.5 bits. If you need real 16 bit resolution you may have problems.

2. 4, 8, 16 and 32x HW averaging are available. You can calculate the speeds possible by using the calculator Search Results: ADC_CALCULATOR_CNV.zip

3. There are the 2 ADCS (with 4 channels) which can be multiplexed to quite a lot of inputs. You just need to check that the ADC input is names ADCxxx0 or ADCxxx1 to be sure which of the connverters it can actually be connected to. Some are named with a or b at the end specifying which ADC channel thay can be connected to.

4. Most ADC inputs are single ended so reference VREFL. There are some that are optionally differential and then they reference their other differential input pair. Also the differential ones can be used in single-ended mode.

5. There are a few pins that are dedicated to ADC functions and others that mux with other functions. The K20 has up to 8 possible mux functions on each pin and so an input may be set as ADC, GPIO, UART, Timer, CAN, etc...

6. The P&E Multilink programmer can be hooked up in JTAG or SWD modes - it is easiest to copy the diagrams for the standard reference boards.

Regards

Mark

Kinetis: µTasker Kinetis support

K20: µTasker Kinetis TWR-K20D72M support  / µTasker Kinetis FRDM-K20D50M support  / µTasker Kinetis TWR-K20D50M support  / µTasker Teensy3.1 support

ADC/DAC: http://www.utasker.com/docs/uTasker/uTaskerADC.pdf

For the complete "out-of-the-box" Kinetis experience and faster time to market

[christopherhuds]

thanks for the reply, but unfortunately i needed to be more specific in my questions:

I am using MK20FN1M0VLQ12.

1. Does it have 4 SAR ADC?

2. Does each ADC need to be used with PGA or is there a bypass?  I can't have signal limitation of 4KHz. 

3. Can each ADC be configured independently/differently for hardware averaging?

4. When using ADCX_SE can I randomly choose between any pin.  for example can I run my signal to ADC0_SE8 as well as it can be run to ADC0_SE9, etc for each ADC0-3?

5. where can i find the schematics for these: "it is easiest to copy the diagrams for the standard reference boards."?

6. is there a difference between OPENSDA and JTAG?  which pins are which on my processor?

[mjbcswitzerland · Accepted solution]

Christopher

MK20FN1M0VLQ12 is indeed the exception with 4 independent ADCs.

1. Yes. (Using HW trigger mode 8 samples can be achieved with a and b inputs in sequence, rather than in parallel)

2. PGA is always optional - if not enabled there is a bypass.

3. Each ADC is fully independent so each one's sampling settings, resolution and HW averaging can be completely different.

4. Each ADC has a MUX to multiple input pins - each sample can be performed with a single MUX setting (from single pin) but the MUX setting can be changed between samples if required.

5. For the K20FN1M Freescale recommends using the TWR-K60 board. The Kinetis K60 120 MHz Tower System Module|Freescale The diagrams are there under the Downloads Tab.

6. JTAG requires more pins. SWD is signal-wire debug so needs only 2 connections (plus GND, RESET).

Full details are in the user manual:

Regards

Mark

Kinetis: µTasker Kinetis support

K20: µTasker Kinetis TWR-K20D72M support  / µTasker Kinetis FRDM-K20D50M support  / µTasker Kinetis TWR-K20D50M support  / µTasker Teensy3.1 support

K60: µTasker Kinetis TWR-K60N512 support  / µTasker Kinetis TWR-K60D100M support  / µTasker Kinetis TWR-K60F120M support

ADC/DAC: http://www.utasker.com/docs/uTasker/uTaskerADC.pdf

For the complete "out-of-the-box" Kinetis experience and faster time to market