Freescale Semiconductor DSP56366 - Manual (Page 193)

Operating Modes
DSP56366 24-Bit Digital Signal Processor User Manual, Rev. 4
Freescale Semiconductor 8-43
NOTE
When operating in normal mode, bit 0 of the mask register must be set to
one, otherwise no input is received.
8.4 Operating Modes
ESAI operating mode are selected by the ESAI control registers (TCCR, TCR, RCCR, RCR and SAICR).
The main operating mode are described in the following paragraphs.
8.4.1 ESAI After Reset
Hardware or software reset clears the port control register bits and the port direction control register bits,
which configure all ESAI I/O pins as disconnected. The ESAI is in the individual reset state while all ESAI
pins are programmed as GPIO or disconnected, and is active only if at least one of the ESAI I/O pins is
programmed as an ESAI pin.
8.4.2 ESAI Initialization
The correct way to initialize the ESAI is as follows:
1. Hardware, software, ESAI individual, or STOP reset.
2. Program ESAI control and time slot registers.
3. Write data to all the enabled transmitters.
4. Configure at least one pin as ESAI pin.
During program execution, all ESAI pins may be defined as GPIO or disconnected, causing the ESAI to
stop serial activity and enter the individual reset state. All status bits of the interface are set to their reset
state; however, the control bits are not affected. This procedure allows the DSP programmer to reset the
ESAI separately from the other internal peripherals. During individual reset, internal DMA accesses to the
data registers of the ESAI are not valid and data read is undefined.
The DSP programmer must use an individual ESAI reset when changing the ESAI control registers (except
for TEIE, REIE, TLIE, RLIE, TIE, RIE, TE0-TE5, RE0-RE3) to ensure proper operation of the interface.
NOTE
If the ESAI receiver section is already operating with some of the receivers,
enabling additional receivers on the fly (i.e., without first putting the ESAI
receiver in the personal reset state) by setting their REx control bits will
result in erroneous data being received as the first data word for the newly
enabled receivers.