Information to program a new driver for Asterisk

I’m interested in developing a new channel driver for a thrid party
telephony card for Asterisk. Is there any “official” document that
explains how to do this? We’ve been looking the doc/channel.txt and
doc/modules.txt in the source, but that’s not a very complete source of
info :slight_smile:

Thanks a lot for your attention.

Christian Peña