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MPC 5644A Etpu setting for 6+1 crank wheel

Question asked by Qiang Chen on Sep 17, 2014
Latest reply on Jan 17, 2015 by Qiang Chen

Hi,


I am using MPC5644A etpu for engine crank signal processing.  The AN4907 and AN4908 provided good documentations and demo code for that purpose.

 

When I used 36-1 crank wheel, the code works fine.  But when I switched to 6+1 crank wheel, the code looks not working well ( etpu_crank_isr was not triggered).   I did not change anything on the code itself except the following parameters (which was calculated by the excel sheet crank_ratios.xls in the AN4707SW):

 

In etpu_gtc.h

#define TEETH_TILL_GAP                                                       6

#define TEETH_IN_GAP                                                          0

#define TEETH_PER_CYCLE                                                  12

#define TCR2_TICKS_PER_TOOTH                                      600

 

In etpu_gtc.c

struct crank_config_t crank_config =

{

  1*(TEETH_TILL_GAP+TEETH_IN_GAP), /* teeth_per_sync */

  (uint24_t)MSEC2TCR1(10), /* blank_time */

  3,             /* blank_teeth */

   0xFFFFFF, /* gap_ratio */

   0x191687, /* win_ratio_normal */

   0x191687, /* win_ratio_across_gap */

   0x16A11E, /* win_ratio_after_gap */

   0x48CE2D, /* win_ratio_after_timeout */

  (uint24_t)MSEC2TCR1(50)  /* first_tooth_timeout */

};

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