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the eppi of bf548 lost field data error in GP3 FS and RX Mode

Question asked by laoyang on Oct 15, 2009
Latest reply on Feb 15, 2010 by JiangW


when the eppi  of bf548 be used in GP3 and RX mode, there is a field to be lost.

we find that  the sync and data lines will be held  when  PPIx_FS3  is high. only hold when PPIx_FS3 is low.


                                                       data                           EPPIx_STATUS

FS3 start low  (always):        field1 and field 2                        0x0000

FS3 start high (always):      field1 and field 2                          0x0000

FS3 low =>hight :              one field                                      0x8010 or 0x0010

FS3 hight =>low:               field1 and field 2                           0x0000

my eppi control:

    eppix_control(ppi) = nEPPI_DIR
                     | XFR_TYPE      /* operation mode */
                     | FS_CFG_SEL(2)   /* GPx mod*/
                     | ICLKGEN   /* Internal Clock Generation */
                     | POLC_SEL(1)    /* FS Edges */
                     | POLS_SEL(0)  /*  the active level of the frame syncs */ 
                     | DLEN_SEL(4)   /* Data Length */
                     | FIFO_RWM_SEL(3)  /* Regular Watermark */
                     | FIFO_UWM_SEL(1); /* Urgent Watermark */


sync timing like this, field 2 lost.

FS3                         _______               ________                _______

                  _______             |________                |________          

data           |_filed1__|_field2__|___1_____|___2___|___1____|___2____|


it is realy no way to setting with software.

is there it 's  a hardware bug ?