CR,
Now all IC should have their 0.1uF caps.
Ron,
Thanks for the comments. In my design update I've added a 0.1uF bypass to the 3V3 pin and changed 10uF to 4.7uF. I also added a Ferrite bead with some 30ohm impedance. Hope this will make the current draw at initial connection within 100mA so the picky USB port has no more complaints.
On my prototype I'm going to remove the 150 ohm resistors on the D+ and D- that I added my mistake. Then possibly change the 10uF to 4.7uF but since the whole device is powered by USB, with a number of 10uF caps in parallel, I'm not sure if this will help. Once I get the ferrite bead I'll add it to my prototype.
I'm looking at the simulation. Still trying to figure out how to model my circuit. I have no data on what cap is on my laptop's mobo. The tool is interesting. I am more used to using SPICE for simulations but I don't do that a lot.
Here is another thing I'm not sure about. According to the FTDI doc, self-powered devices should have a different power descriptor, probably not the one by default (bus powered). I do have a battery inside with 5V regulator. I wonder if I need to mess with EEPROM on the FT232R chip at all. Also there is a voltage divider to keep the chip on reset until USB connection. I wonder if that is necessary. I can always say that my device should either be plugged into the USB port with battery switched off or standalone without USB connection and powered by battery. I don't have a voltage selector circuit either. It's like Diecimila.
OSPLv2_4_11.pdf (53.9 KB)