Samsung S5PC100, User Manual

Page: 1635 / 1863

I2S CONTROLLER(5.1CH) S5PC100 USER’S MANUAL (REV1.0)
10.2-2
3 BLOCK DIAGRAM
Register
File
TxR
Channel
Control
TxDMA
FSM
RxDMA
FSM
Clock
Control
Tx Shift
Register
Rx Shift
Register
TxFIFO
RxFIFO
TxDREQ TxDACK
APB
RxDREQ
RxDACK
I2SBCLK
I2SLRCLK
I2SSDO 0
I2SSDI
I2SCODCLKO
I2SCODCLKI
Tx Shift
Register
Tx Shift
Register
I2SSDO 1
I2SSDO 2
AHB DMA
D2_SS
Bus
PCLK Domain
Codec CLK
Domain
S
y
n
c
h
r
o
n
iz
e
r
Synchronizer
Synchronizer
S
y
n
c
h
r
o
n
iz
e
r
S
y
n
c
h
r
o
n
iz
e
r
Core CLK
Domain
Figure 10.2-1 I2S-Bus Block Diagram
4 FUNCTIONAL DESCRIPTIONS
I2S interface consists of register bank, FIFOs, shift registers, clock control, DMA finite state machine, and channel
control block as shown in Figure 10.2-1. Note that each FIFO has 32-bit width * 64 depth structure, which contains
left/ right channel data. Therefore, FIFO access and data transfer are handled with left/ right pair unit. Figure 10.2-
1 shows the functional block diagram of I2S interface.
4.1 MASTER/ SLAVE MODE
Set IMS bit of I2SMOD register to select master or slave mode. In master mode, I2SSCLK and I2SLRCLK are
generated internally and supplied to external device. Therefore a root clock is needed for generating I2SSCLK
and I2SLRCLK. The I2S pre-scaler (clock divider) generates a root clock with divided frequency from internal
system clock. In external master mode, the root clock is fed directly from external I2S. The I2SSCLK and
I2SLRCLK are supplied from the pin (GPIOs) in slave mode.
Master/ Slave mode is different with TX/RX. Master/Slave mode presents the direction of I2SLRCLK and
I2SSCLK. The direction of I2SCDCLK (This is only auxiliary) is not a concern. If I2S bus interface transmits clock
signals to I2S codec, I2S bus is master mode. But if I2S bus interface receives clock signal from I2S codec, I2S
bus is slave mode. TX/RX mode indicates the direction of data flow. If I2S bus interface transmits data to I2S
codec, this is TX mode. Conversely, I2S bus interface receives data from I2S codec that is RX mode. Let us
distinguish Master/ Slave mode from TX/RX mode.