MC9S12T64 Datasheet, PDF (424/608 Pages) Motorola, Inc – Specification

Freescale Semiconductor, Inc.
Serial Communications Interface (SCI)
Register Descriptions
This section consists of register descriptions in address order. Each
description includes a standard register diagram with an associated
figure number. Writes to a reserved register location do not have any
effect and reads of these locations return a zero. Details of register bit
and field function follow the register diagrams, in bit order.
SCI Baud Rate
Registers
(SCIxBDH/L)
Where: x = 0 for SCI0, or 1 for SCI1
Address Offset: $00C8 (SCI0BDH), $00D0 (SCI1BDH)
Bit 7
6
5
4
3
Read:
0
0
0
SBR12 SBR11
Write:
Reset:
0
0
0
0
0
2
SBR10
0
1
SBR9
0
Bit 0
SBR8
0
= Unimplemented or Reserved
Address Offset: $00C9 (SCI0BDL), $00D1 (SCI1BDL)
Bit 7
6
5
Read:
Write:
SBR7
SBR6
SBR5
Reset:
0
0
0
4
SBR4
0
3
SBR3
0
2
SBR2
1
1
SBR1
0
Bit 0
SBR0
0
Read: anytime. If only SCIxBDH is written to, a read will not return the
correct data until SCIxBDL is written to as well, following a write to
SCIxBDH.
Write: anytime. Writing to SCIxBDH has no effect without writing to
SCIxBDL, since writing to SCIxBDH puts the data in a temporary
location until SCIxBDL is written to.
The SCI Baud Rate Register is used by the counter to determine the
baud rate of the SCI. The formula for calculating the baud rate is:
SCI baud rate = Bus Clock / (16 x BR),
MC9S12T64Revision 1.1.1
Serial Communications Interface (SCI)
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