AnsweredAssumed Answered

VADC on VF6xx

Question asked by Antonio Boi on Jun 11, 2014
Latest reply on Jun 12, 2014 by Antonio Boi

I'm trying to use the module VADC of Vybrid intending to capture some video PAL frames.


Here are the test conditions:
- I used the Vybrid Reference Manual Rev. 5, 07/2013 to configure all the registers
- Toradex Module VF61 with a MVF61NS151CMK50 chip
- 4 Input VADC discoupled with 47nF e 75ohm to ground signal
- A standard PAL signal on each input channel originated from a SONY videocamera


Modules configuration:


- PLL6 configured to 1064 MHz according to the 9-3 RM table
- PLL6 divided by 2 through the CCM_CACRR[PLL6_DIV_CLOCK] register
- PLL6 configured as a source of the VADC through the CCM_CSCMR1[VADC_CLK_SEL]register
- Clock of the VADC divided by 4 through the CCM_CSCDR1[VADC_DIV] register to obtain 133MHz
- Chosen VCAFE_VIN_0 through the AFE_INPFLT[mux_enlf] register
- Set pull-down VCAFE_VIN_1, VCAFE_VIN_2, VCAFE_VIN_3 through the AFE_OFFDRV[input_pulldown_en] register
- Enabled the clock to VADC through the CCM_CSCDR1[VADC_EN] register
- Introduced a 500ms delay


Reading the  VDEC_VIDMOD[PAL detected] register I always obtain a 0 value: unrecognized PAL .
Furthermore I read the VDEC_VIDMOD[m625] register always active, with or without input signal.


So, why is the VDEC_VIDMOD[PAL detected] register always null, nevertheless I connected a signal?
Is it necessary to configure some other register (AFE or VDEC) so that the VADC system could recognize the PAL standard?


Antonio Boi