MC145572PB Freescale Semiconductor, MC145572PB Datasheet - Page 154

• Manufacturer Part Number: MC145572PB
• Manufacturer: Freescale Semiconductor

Specifications of MC145572PB

• Number Of Line Interfaces: 1
• Control Interface: HDLC
• Lead Free Status / Rohs Status: Not Compliant

9–6
9.2.3
LT Mode Initialization and Activation
LT initialization is very similar to NT initialization except that the automatic eoc mode is not available.
Trinal checking of received eoc commands is enabled. When the U–interface transceiver is operated
as an LT, the software initiates eoc messages by writing into R6. Correct operation of the eoc mes-
sage at the NT1, as defined in ANSI T1.601–1992, is indicated by the LT receiving the echoed eoc
message in R6. This is shown at a very high level in LTISR1.
An initialization and activation procedure for LT mode follows with numbers in hexadecimal:
Procedure LTACT1();
/*
PURPOSE:
The activation procedure LTACT1 resets the U–interface transceiver, calls the initializa-
tion routine LTINIT1, sets activate request, and waits for interrupts.
*/
BEGIN
NR0(b3) <–
NR0(b3) <–
CALL LTINIT1();
If NR1 = 0 then NR2 (b3) <– 1;
Wait for interrupt;
Other code;
END;
Procedure LTINIT1()
/*
PURPOSE:
The initialization procedure LTINIT1 puts the LT configured U–interface transceiver into
eoc trinal–check mode and selects the M4 channel trinal consecutive check mode of opera-
tion. It also sets default values for the M4, M5, and M6 channels. Activation interrupts
are also enabled. This routine should always be executed just prior to setting Activation
Request NR2(b3) = 1 or when the activation in progress interrupt occurs in response to the
MC145572 detecting a wakeup tone.
*/
BEGIN
BR0
BR1
BR2
BR9
BR10(b0) =
OR7(b0) =
BR10(b0) =
R6
NR4
return ( ) ;
END;
=
=
=
=
=
=
1;
0;
7F;
7F;
F0;
8C;
1;
1;
0;
1FF; /* Eoc defaults to Return to Normal message with NT1 addressed and d/m
E;
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/* Assert software reset. Only required
/* De–assert software reset. Only required at power–up initialization.*/
/* act = 0, dea = 1, other bits to ANSI T1.601–1992 reserved status. */
/* Force an M4 channel interrupt to occur when received act changes to a
/* M5 and M6 channels to ANSI T1.601–1992 reserved condition. febe Input
/* Select eoc trinal check, M4 Verified act mode, M5/M6 update on every
/* Select Init Group of registers */
/* Enable trinal checking of M4 act and sai bits. */
/* Deselect Init Group. */
/* Enable eoc, M4 and activation interrupts. */
at power–up initialization.*/
/*
1 from a zero. */
= one. */
frame, and transmited febe is Computed nebe. */
bit set to one. */
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MC145572
/*
Set activation request bit */
Wait for result of Activation */
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