Datasheet
®
15 PCM3501
SERIAL
INTERFACE
M/S (PIN 6) MODE FS (PIN) BCK (PIN 8)
0 Slave Input Input
1 Master Output Output
TABLE II. Master/Slave Mode Selection.
SYMBOL DESCRIPTION MIN TYP MAX UNITS
t
BCKP
BCK Period 2400 16000 ns
t
BCKH
BCK Pulse Width HIGH 1200 8000 ns
t
BCKL
BCK Pulse Width LOW 1200 8000 ns
t
CKFS
Delay Time BCK Falling Edge to FS – 40 40 ns
t
FSW
FS Pulse Width HIGH t
BCKP
– 60 t
BCKP
t
BCKP
+ 60 ns
t
FSP
FS Period 1/f
S
t
DISU
DIN Set Up Time to BCK Rising Edge 60 ns
t
DIHD
DIN Hold Time to BCK Rising Edge 60 ns
t
CKDO
Delay Time BCK Falling Edge to DOUT 0 80 ns
t
R
Rising Time of All Signals 30 ns
t
F
Falling Time of All Signals 30 ns
FIGURE 8. Serial Interface Timing for Master Mode.
MASTER/SLAVE OPERATION
The serial interface supports both Slave and Master Mode
operation. The mode is selected by the M/S input (pin 6).
Table II shows mode and pin settings corresponding to the
M/S input selection. Figure 9 shows connections for Slave
and Master mode operation.
FIGURE 9. Slave and Master Mode Connections.
Slave Mode Operation
In Slave Mode, the FS and BCK pins are inputs to the
PCM3501. Both FS and BCK should be derived from the
system clock signal (XTI or SCKIO) to ensure proper
synchronization. Slave Mode is best suited for applications
where the DSP or controller is capable of generating the FS,
BCK, and system clocks using an on-chip serial port and/or
timing generator.
Master Mode Operation
In Master Mode operation, both FS and BCK are clock
outputs generated by the PCM3501 from the system clock
input (XTI, SCKIO, or a crystal). In Master Mode, the timing
and phase relationships between system clock, FS, and BCK
are managed internally to provide optimal synchronization.
t
FSW
t
CKFS
t
BCKP
t
BCKH
t
DISU
t
DIHD
t
BCKL
t
CKDO
t
FSP
NOTES: Timing measurement reference level is (V
IH
/V
IL
)/2. Rising and falling time is measured from
10% to 90% of IN/OUT signal swing. Load capacitance of DOUT, FS, BCK signal is 50pF.
0.5V
DD
0.5V
DD
0.5V
DD
0.5V
DD
FS
(output)
BCK
(output)
DIN
(input)
DOUT
(output)
XTI
FS (input)
BCK (input)
DIN
DOUT
M/S
TSC
GND
GND
Controller
System
Clock
Slave Mode
PCM3501
XTI
FS (output)
BCK (output)
DIN
DOUT
M/S
TSC
V
DD
GND
PCM3501
System
Clock
Controller
Master Mode