
Signal Descriptions
Symphony DSP56724/DSP56725 Multi-Core Audio Processors, Rev. 0
Freescale Semiconductor
2-13
2.2.9
Enhanced Serial Audio Interface Signals (ESAI, ESAI_1, ESAI_2,
ESAI_3)
There are four groups of ESAI pins: ESAI, ESAI_1, ESAI_2 and ESAI_3. ESAI and ESAI_1 pins are used
by the DSP Core-0. ESAI_2 and ESAI_3 are used by DSP Core-1. The next four tables show the pins for
each ESAI group.
Pin switching between ESAI modules features are supported: ESAI can switch pins with ESAI_2, and
ESAI_1 can switch pins with ESAI_3. The switch controls are pin by pin.
Table 2-13. Enhanced Serial Audio Interface Signals (ESAI)
Signal Name
Signal Type
State during
Reset
Description
HCKR
Input or Output
GPIO
Disconnected
ESAI’s High Frequency Clock for Receiver
When programmed as an input, this signal provides a high frequency clock
source for the ESAI receiver (as an alternative to the DSP core clock).
When programmed as an output, this signal can serve as a high-frequency
sample clock (for example, for DACs or as an additional system clock.
PC2
Input, Output, or
Disconnected
GPIO Port C2
When the ESAI is configured as GPIO, this signal is individually
programmable as input, output, or internally disconnected.
SRCK
Output
S/PDIF Receive Clock
— This Pin can be used as S/PDIF receive clock
output; this clock is generated by the internal S/PDIF’s DPLL, controlled
by the ERC0 bits in Pin MUX Control Register of the Chip Configuration
Module.
The default state after reset is GPIO disconnected.
Uses an internal pull-down resistor.
HCKT
Input or Output
GPIO
Disconnected
ESAI’s High Frequency Clock for Transmitter
When programmed as an input, this signal provides a high frequency clock
source for the ESAI transmitter (as an alternative to the DSP core clock).
When programmed as an output, this signal can serve as a high frequency
sample clock (for example, for external DACs) or as an additional system
clock.
PC5
Input, Output, or
Disconnected
GPIO Port C5
When the ESAI is configured as GPIO, this signal is individually
programmable as input, output, or internally disconnected.
STCLK
Input
S/PDIF Transmit Clock
— This Pin can be used as S/PDIF transmit clock
input; controlled by the ClkSrc_Sel bits in the S/PDIF PhaseConfig
Register.
The default state after reset is GPIO disconnected.
Uses an internal pull-down resistor.