Hi Sribangaram,
The pins are multifunction function pins that are set by program. In other word, you can appoint these pins to one of the defined function. But, you cannot use same pin with different function simultaneously
GPIOs : they are general purpose I/O pins. These pins may be pull_down, pull_high or floating during reset.
1.) ( pin12 ) use as GPIO or PCM_clk or PWM
For PCM case, you will need to group with
PCM_CLK : pcm clock ( pin 12 )
PCM_DIN : pcm data out ( pin 38 )
PCM_DOUT : pcm data in ( pin 40 )
PCM_FS : pcm frame sync ( pin 35 )
Pin 8, 10 : can use as UART
UART_TxD : UART Tx data
UART_RxD : UART Rx data
Pin19, 21, 23 : for SPI
MOSI : SPI data input
MISO : SPI data out
SCLK : SPI clock signal
They work as a group
pin27, 28 ( I2C )
SDA0 : Group 0 Serial data
SCL0 : Group 0 Serial clock
pin3, 5 ( I2C )
SDA1 : Group 1 Serial data
SCL1 : Group 1 Serial clock
Roger