How to calculate the delay time of the Programmable Delay Block (PDB)?

[小勇邹]

Hi,

How to calculate the delay time of the Programmable Delay Block (PDB) in KM34?

For example, if setting PDB0_CH0DLY0=200, how to calculate the delay time?

And I cannot find the clock source for PDB in the data sheet. Can you also tell me the clock source of PDB?

[alejandra_guzman]

The PDB clock reference can be found at the KM34 Reference Manual Chapter 5 Clock Distribution 

To calculate a PDB channel delay you need to use the configurable PDB registers bits:

PDB Clock = Bus Clock / ( Preescaler x Mult )

Preescaler -- PDBx_SC[PREESCALER]

Mult -- PDBx_SC[MULT]

Channel Delay = PDB Clock / PDBx_CHnDLY0  

For example
Bus Clock = 24 MHz

Preescaler = 011 (8 times) 

Mult = 01 ( factor is 10 )

PDBx_CHnDLY0 = 300 

PDB Clock = 24 MHz / ( 8 x 10 ) = 300 kHz            1 PDB Count = 3.33 us

Channel Delay = 300 kHz / 300 = 1 kHz                  Channel timer = 1 ms