MC68HC08AZ16 Datasheet, PDF (172/527 Pages) Motorola, Inc – HCMOS Microcontroller Unit

Serial Communications Interface Module (SCI)
Functional description
Functional description
Figure 1 shows the structure of the SCI module. The SCI allows
full-duplex, asynchronous, NRZ serial communication between the MCU
and remote devices, including other MCUs. The transmitter and receiver
of the SCI operate independently, although they use the same baud rate
generator. During normal operation, the CPU monitors the status of the
SCI, writes the data to be transmitted, and processes received data.
During DMA transfers, the DMA fetches data from memory for the SCI
to transmit and/or the DMA stores received data in memory.
Table 1. SCI I/O register summary
Register Name
Bit 7 6
5
4
3
2
1 Bit 0 Addr.
SCIControlRegister1(SCC1) LOOPS ENSCI TXINV M WAKE ILTY PEN PTY $0013
SCIControlRegister2(SCC2) SCTIE TCIE SCRIE ILIE TE RE RWU SBK $0014
SCIControlRegister3(SCC3) R8 T8 DMARE DMATE ORIE NEIE FEIE PEIE $0015
SCIStatusRegister1(SCS1) SCTE TC SCRF IDLE OR NF FE PE $0016
SCI Status Register 2 (SCS2)
BKF RPF $0017
SCI Data Register (SCDR)
$0018
SCI Baud Rate Register (SCBR)
SCP1 SCP0
SCR2 SCR1 SCR0 $0019
= Unimplemented
Data format
The SCI uses the standard non-return-to-zero mark/space data format
illustrated in Figure 6.
3-sci
MOTOROLA
Serial Communications Interface Module (SCI)
MC68HC08AZ32
171