PDB interrupt periodicity

[nadine]

Hi,

I'm working with a FRDM-K64F board, with KSDK_v2 release.

I'm using the PDB to hardware trigger the DAC. I'm in trouble with the usage of the PDB prescalerDivider, the PDB dividerMultiplicationFactor,

the DAC interval value, the PDB delay value, and the PDB modulus value ...

Is there an application note availabe to explain the configuration to use to obtain a requested PDB interruption periodicity ?

Following settings give a rough interruption frequency of 0.9 MHz but I'm not able to explain ...

I have not succeed in reaching  a 1.2 MHz frequency.

pdbConfigStruct.prescalerDivider = kPDB_PrescalerDivider1;

pdbConfigStruct.dividerMultiplicationFactor = kPDB_DividerMultiplicationFactor1;

PDB_SetModulusValue(PDB_BASE, 2);

PDB_SetCounterDelayValuePDB_BASE, 2);

PDB_SetDACTriggerIntervalValue(PDB_BASE, DAC_CHANNEL, 800);

See linked file (oscilloscope output for a sinus periodic curve of 4096 points)

Thanks for your help,

Best Regards

Nadine

[isaacavila]

Hello Nadine,

I invite you to check this video that explains the PDB module and shows a basic program using Kinetis SDK 1.3. You can understand its structure and then be able to configure your PDB correctly.

Programmable Delay Block|NXP

If you still have doubts then you can let me know it and I would try to reply to them.

I hope this can help you!

Best Regards,

Isaac Avila

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[nadine]

Hi Isaac,

Thanks fo the answer. It helps me going on with this topic.

Now, I want to configure the PDB using an external trigger input souce (EXTRG pin).

Up to 15 trigger input sources are available and user-selectable through the TRGSEL bits of

the PDB Status and Control register.

In the K64 Sub-Family Reference Manual, Chapter 39 PDB , section 39.3.1 PDBx_SC,

to set up the TRGSEL bits, it is written to "refer to the chip configuration

details for the actual PDB input trigger connections" ... Where can I find these information ?

Best regards

Nadine

[isaacavila · Accepted solution]

Hello Nadine,

This chip-specific information in mainly located in Chapter 3: Chip Configuration, for this case, in section 3.8.1.1.2 PDB Input trigger connection there is a table (Table 3-57) that refers to all of these input triggers:

All other chip-specific information like back-to-back acknowledgement connnections, PDB interconnections and other are also located in this section.

I hope this can help you!

Best Regards,

Isaac Avila

[jordangarcia]

Hi Isaac:

Where can I find this manual? 

Regards
Jordan García 

[isaacavila]

Hello Jordan,

You can download this Reference Manual from K64's web page at www.nxp.com, please refer to next link and be aware to download the proper RM according your part number.

ARM Cortex-M4|Kinetis K64 120 MHz 32-bit MCUs|NXP 

Regards,

Isaac