Thanks Shazam and Slimfish, I’m a bit dazzled about your conversation. Seeed didn’t design the circuits, you may see from the box that it’s the work of Mr. Cai Xiaoguang (aka Bure if you read the source code), a very veteran electrical engineer and luckily our closest partner. We are more apprentices in this product, I’m consolidating all available resources from inside and outside Seeed Studio to make DSO nano better.
I’m keeping consolidating the ideas from forum, blog ,email or anywhere I can see them. We will add the charging circuit in next revision soon, along with other improvements <5$ for current version. I will generate a list of fix/improvement/TBD soon.
For SP3232, we will modify it in the next version with TC1240.
Thank you so much for the suggestions! I will get back to you soon.