MC68HC11EA9 Datasheet, PDF (50/58 Pages) Motorola, Inc – 8 BIT HCMOS SINGLE CHIP MICROCONTOROLLER WITH A/D CONVERTER

Freescale Semiconductor, Inc.
SCBDH, SCBDL — SCI Baud Rate Select High, SCI Baud Rate Select Low
$1028
RESET:
$1029
RESET:
BIT 7
BTST
0
SBR7
0
6
BSPL
0
SBR6
0
5
—
0
SBR5
0
4
SBR12
0
SBR4
0
3
SBR11
0
SBR3
0
2
SBR10
0
SBR2
1
1
SBR9
0
SBR1
0
$1028, $1029
BIT 0
SBR8
0
SBR0
0
High
Low
BTST — Baud Register Test (TEST)
Factory test only
BSPL — Baud Rate Counter Split (TEST)
Factory test only
Bit 5 — Not implemented
Always reads zero
SBR[12:0] — SCI Baud Rate Select Bits
Use the following formula to calculate SCI baud rate. Refer to the table of baud rate control values for
example rates:
SCI baud rate = EXTAL ÷ (32 • BR)
where BR is the contents of SBR[12:0] in SCBDH,L (BR = 1, 2, 3 ... 8191 decimal, or BR = $0001,
$0002, $0003 ... $1FFF hexadecimal)
BR = 0 disables the baud rate generator.
Table 22 Baud Rate Selection
Target
Baud
Rate
110
312
300
600
1200
2400
4800
9600
19.2K
38.4K
Crystal Frequency (XTAL)
8 MHz
12 MHz
16 MHz
Dec Value Hex Value Dec Value Hex Value Dec Value Hex Value
2272
$08E0
3409
$0D51
4545
$11C1
156
78
2500
$09C4
3333
$0D05
833
$0341
1250
$04E2
1666
$0682
416
$01A0
625
$0271
833
$0341
208
$00D0
312
$0138
416
$01A0
104
$0068
156
$009C
208
$00D0
52
$0034
78
$004E
104
$0068
26
$001A
39
$0027
52
$0034
13
$000D
20
$0014
26
$001A
—
—
—
—
13
$000D
MC68HC11EA9
50
For More Information On This Product,
MC68HC11EA9TS/D
Go to: www.freescale.com