fm transmitter audio input via usb

Hi;
I will design fm transmitter with si4713. But audio input will be via usb. Can I directly connect usb D+ and D- pins to si4713 (digital input pins)?
or codec or anything is required between usb port and si4713?
Thanks in advance

Presumably you want to transmit analog audio ?

or do you want to transmit it digitally and decode it at the other end ?

Dave

USB is not digital audio. Compare with a headset that can be connected to a USB port in a PC. Headset must contain a MCU that can talk the USB protocol and do all interfacing and handshaking before the computer will deliver a single bit of sound-related information. That is how it work or else would not a PC be able to differ a headset from a mouse. Besides that must you also control all other registers in Si4713 for frequency, modulation, power level, selection of digital or analog input...... You need a MCU between Si4713 and USB port, programmed to be able to talk to all parts of Si4713 in one direction and be able to handle USB protocol in other direction. And then must you also program a driver and GUI for PC.
Documentation, demo-software/hardware and code-examples are available at Silicon Labs.

yeah I should have phrased that better... digital signal rather than digital audio. that could lead to confusion huh :)

Dave

Kafeman,
I will use mcu(c8051f342) and programmed it via jtag(C2 interface). and also i will change frequency,modulation,power level and RDS parameters with keypad. But in my design, there will be two audio inputs. One is RCA and the other is USB. Between RCA and si4713 there are only two capacitors for ac-coupled(in si4713 datasheet). But between usb and si4713, is any process required?
thanks for replies.

Digital audio and USB protocol are very different animals. Digital sound in this chip is handled by three inputs, Din, Dclk, Dfs were actual sound information for both right and left channel are coded bitstreams in Din.