Hey guys,
Can I please get some feedback on a schematic for a USB/Bluetooth project before ordering the PCBs?
BLE_USB_KBD_v0.8.PDF 462.85KB
18 downloads
The schematic is divided into 4 sections: power and Li-Po charger on the top left, a connector to external keyboard on the top right, MSP430F5502 on the bottom left and Bluetooth module connections near the bottom right. The two connectors down below are for programming the MSP and the Bluetooth module.
The power and Li-Po section should allow a 1-cell Li-Po battery to be charged when USB is plugged in at 500mA charge rate. The 5V booster RT9361A steps 3.0V-4.2V of the Li-Po to 5V to power the PS/2 mouse on the external keyboard connected to CONN. This +5V is then fed into the 3.3V LDO RT9030-33GU5 to supply the rest of the circuit.
When USB is plugged in, the F5502 should be able to detect the connection and enumerates. I followed TI's recommended USB schematic layout with a BSL button. The resonator used is a 4MHz resonator.
The Bluetooth module should work correctly, as it does standalone on another test PCB.
What I'm a bit worried about is if the RT9030-33GU5 3.3V output is going to interfere with the F5502's LDO output on pin 42 (VUSB). As for the DVCCx and AVCCx, I don't have any capacitors near them mainly because I don't have much space left on the PCB but I hope that the MSP430 would still work without them. Would it be a problem?
I've checked the design a few times but I always manage to find some possible screw-ups a few days after ordering PCBs.
Thanks for your help.