Microchip Technology dsPIC30F - Codec Interface Basics and Terminology

dsPIC30F Family Reference Manual
DS70069C-page 22-8 © 2004 Microchip Technology Inc.
22.3 Codec Interface Basics and Terminology
The interface protocols supported by the DCI require the use of a Frame Synchronization (FS)
signal to initiate a data transfer between two devices. In most cases, the rising edge of FS starts
a new data transfer. In any codec application there is, at a minimum, a controller and a codec
device. Either device may produce FS. The device that generates FS is the master device.
Conceptually, the master device does not have to be the transmitting or receiving device. Various
connection examples are shown in Figure 22-1. The frequency of the FS signal is usually the
system sampling rate, fs.
Figure 22-1: Codec CONNECTION EXAMPLES
Note: The details given in this section are not specific to the DCI module. This discussion
is intended to provide the user some background and terminology related to the
digital serial interface protocols found in most codec devices.
Codec
SCK
FS
SDI
Controller
SDO
CSCK
COFS
CSDO
CSDI
Codec
SCK
FS
SDI
SDO
Codec is Master
dsPIC
®
(Controller)
CSCK
COFS
CSDO
CSDI
Codec
SCK
FS
SDI
SDO
Controller is Master
CSCK
COFS
CSDO
CSDI
A/D #1
Daisy-Chained Configuration
A/D #2
FSO
FS
SCK
SDO
FSO
FS
SCK
SDO
CSCK
COFS
CSDI
to Other Devices
Codec
SCK
FS
SDI
SDO
Codec Generates SCK
CSCK
COFS
CSDO
CSDI
(See Note)
External Controller is Master
Note: Codec oscillator circuit generates SCK signal.
dsPIC
®
(Controller)
dsPIC
®
(Controller)
dsPIC
®
(Controller)
dsPIC
®
(Controller)