Hi, TI
We've developed a board with OPT8241 and OPT9221 with reference to CDK. Currently, signals related with OPT9221 are all OK, but the modulation output signals (ILLUM_EN/ILLUM_P/N) of OPT8241 are not work.
Firstly, we set environments as follows:
- All voltages of OPT8241 and OPT9221 are setting according to the datasheet, and VSUB_BIAS set to -5v.
- OPT9221's sysclk is 48MHz (MCLK to opt8241 is also 48MHz)
- OPT9221 loads it's firmware (0v23) from EEPROM.
- Keep all register of OPT9221 and OPT8241 in reset state (TG/DE register read/write are OK)
Then, we write to TG's 0x80 register with TG_DIS = 0 to make TG to work
After that, we check the signals from oscilloscope. The DVP (or Generic parallel ) signals of OPT9221 are OK. The signals between OPT9221 and OPT8241 are OK. But the illumination modulation signals of OPT8241 is not working as expected:
- ILLUM_EN is always low.
- ILLUM_N is always HIGH
- ILLUM_P is always low
My questions are :
- Is there any register must be set before TG_DIS=0 to make ILLUM_X signals to output?
- Anything else we should check in the hardware?
- Besides, ILLUM_MOD_FB and IO_MOD_REF are connected together, and we found it's like gated 24MHz clock in the oscilloscope, is it OK?
Thanks in advance.
Yao
