I see, I see... peek and poke seem to be very powerful since you can access the SFRs the only issue, I have been exploring for 3 hours, is that the reference manual (my opinion) is poor documented: bit fields are not enough explained, names of registers and bit fields are not clear (they change on different paragraphs), there are no examples, etc. So it is quite difficult to configure the peripherals. I have done this kind of before with other processors in Linux (mainly Freescale i.MX) but those RM have >5K pages and all is clearly documented. I guess the best way is understand how to configure the peripherals is to study the esp-idf framework: much more work than reading a RM :-(.
I will keep testing.