MC68HC08AS32 Datasheet, PDF (179/280 Pages) Motorola, Inc – M68HC08 Family of 8-bit microcontroller units (MCUs)

12.8.6 SCI Data Register
The SCI data register is the buffer between the internal data bus and the receive
and transmit shift registers. Reset has no effect on data in the SCI data register.
Address: $0018
Bit 7
6
Read: R7
R6
Write: T7
T6
Reset:
5
4
3
2
R5
R4
R3
R2
T5
T4
T3
T2
Unaffected by reset
1
Bit 0
R1
R0
T1
T0
Figure 12-14. SCI Data Register (SCDR)
R7/T7–R0/T0 — Receive/Transmit Data Bits
Reading address $0018 accesses the read-only received data bits, R7–R0.
Writing to address $0018 writes the data to be transmitted, T7–T0. Reset has
no effect on the SCI data register.
12.8.7 SCI Baud Rate Register
The baud rate register selects the baud rate for both the receiver and the
transmitter.
Address:
Read:
Write:
Reset:
$0019
Bit 7
6
5
4
3
2
1
R
R
SCP1
SCP0
R
SCR2
SCR1
0
0
0
0
0
0
0
R
= Reserved
Figure 12-15. SCI BAUD Rate Register (SCBR)
Bit 0
SCR0
0
SCP1 and SCP0 — SCI Baud Rate Prescaler Bits
These read/write bits select the baud rate prescaler divisor as shown in Table
12-6. Reset clears SCP1 and SCP0.
Table 12-6. SCI Baud Rate Prescaling
SCP1:SCP0
00
01
10
11
Prescaler Divisor (PD)
1
3
4
13
MC68HC08AS32 — Rev. 4.1
Freescale Semiconductor
Data Sheet
179