> Dear Oliver, > > I?ve done some tests with the CAM reader from Digital Devices based on Sony > CXD2099 chip and I noticed some issues with some CAM: > * SMIT CAM : working fine > * ASTON CAM : working fine, except that it's crashing quite regularly > * NEOTION CAM : no stream going out but access to the CAM menu is ok > > When looking at the CXD2099 driver code, I noticed the CAM clock (fMCLKI) is > fixed at 9MHz using the 27MHz onboard oscillator and using the integer > divider set to 3 (as MCLKI_FREQ=2). > > I was wondering if some CAM were not able to work correctly at such high > clock frequency. > > So, I've tried to enable the NCO (numeric controlled oscillator) in order to > setup a lower frequency for the CAM clock, but I wasn't successful, it's > looking like the frequency must be around the 9MHz or I can't get any > stream. > > Do you know a way to decrease this CAM clock frequency to do some testing? > > Best regards, > Sebastien. Weird that the frequency would pose a problem for those CAMs. The CI spec [1] explains that the minimum byte transfer clock period must be 111ns. This gives us a frequency of ~9MHz. Anyway, wouldn't it be wiser to base MCLKI on TICLK ? -- Issa [1] http://www.dvb.org/technology/standards/En50221.V1.pdf -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
