Motorola DSP56301 - Manual (Page 217)

ESSI Programming Model
Enhanced Synchronous Serial Interface (ESSI) 7 -19
Enable (TEIE) bits. In Network mode, if you clear the appropriate TE bit and set it again, then
you disable the corresponding transmitter (0, 1, or 2) after transmission of the current data
word. The transmitter remains disabled until the beginning of the next frame. During that time
period, the corresponding SC (or
STD in the case of TX0) signal remains in a high-impedance
state. The CRB bits are cleared by either a hardware RESET signal or a software RESET
instruction.
Table 7-4. ESSI Control Register B (CRB) Bit Definitions
Bit Number Bit Name Reset Value Description
23 REIE 0 Receive Exception Interrupt Enable
When the REIE bit is set, the DSP is interrupted when both RDF and ROE
in the ESSI status register are set. When REIE is cleared, this interrupt is
disabled. The receive interrupt is documented in Section 7.3.3,
Exceptions, on page 7-7. A read of the status register followed by a read
of the receive data register clears both ROE and the pending interrupt.
22 TEIE 0 Transmit Exception Interrupt Enable
When the TEIE bit is set, the DSP is interrupted when both TDE and TUE
in the ESSI status register are set. When TEIE is cleared, this interrupt is
disabled. The use of the transmit interrupt is documented in Section
7.3.3,
Exceptions, on page 7-7. A read of the status register, followed by
a write to all the data registers of the enabled transmitters, clears both
TUE and the pending interrupt.
21 RLIE 0 Receive Last Slot Interrupt Enable
Enables/disables an interrupt after the last slot of a frame ends when the
ESSI is in Network mode. When RLIE is set, the DSP is interrupted after
the last slot in a frame ends regardless of the receive mask register
setting. When RLIE is cleared, the receive last slot interrupt is disabled.
The use of the receive last slot interrupt is documented in Section 7.3.3,
Exceptions, on page 7-7. RLIE is disabled when the ESSI is in
On-Demand mode (DC = $0).
20 TLIE 0 Transmit Last Slot Interrupt Enable
Enables/disables an interrupt at the beginning of the last slot of a frame
when the ESSI is in Network mode. When TLIE is set, the DSP is
interrupted at the start of the last slot in a frame regardless of the transmit
mask register setting. When TLIE is cleared, the transmit last slot interrupt
is disabled. The transmit last slot interrupt is documented in Section
7.3.3,
Exceptions, on page 7-7. TLIE is disabled when the ESSI is in
On-Demand mode (DC = $0).
19 RIE 0 Receive Interrupt Enable
Enables/disables a DSP receive data interrupt; the interrupt is generated
when both the RIE and receive data register full (RDF) bit (in the SSISR)
are set. When RIE is cleared, this interrupt is disabled. The receive
interrupt is documented in Section 7.3.3,
Exceptions, on page 7-7. When
the receive data register is read, it clears RDF and the pending interrupt.
Receive interrupts with exception have higher priority than normal receive
data interrupts. If the receiver overrun error (ROE) bit is set (signaling that
an exception has occurred) and the REIE bit is set, the ESSI requests an
SSI receive data with exception interrupt from the interrupt controller.