mc68hc908sr12 Freescale Semiconductor, Inc, mc68hc908sr12 Datasheet - Page 262

• Manufacturer Part Number: mc68hc908sr12
• Description: M68hc08 Microcontrollers Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

Serial Communications Interface (SCI)
16.5.3 Receiver
16.5.3.1 Character Length
16.5.3.2 Character Reception
Data Sheet
262
Figure 16-5
The receiver can accommodate either 8-bit or 9-bit data. The state of the
M bit in SCI control register 1 (SCC1) determines character length.
When receiving 9-bit data, bit R8 in SCI control register 2 (SCC2) is the
ninth bit (bit 8). When receiving 8-bit data, bit R8 is a copy of the eighth
bit (bit 7).
During an SCI reception, the receive shift register shifts characters in
from the RxD pin. The SCI data register (SCDR) is the read-only buffer
between the internal data bus and the receive shift register.
After a complete character shifts into the receive shift register, the data
portion of the character transfers to the SCDR. The SCI receiver full bit,
SCRF, in SCI status register 1 (SCS1) becomes set, indicating that the
received byte can be read. If the SCI receive interrupt enable bit, SCRIE,
in SCC2 is also set, the SCRF bit generates a receiver CPU interrupt
request.
Serial Communications Interface (SCI)
shows the structure of the SCI receiver.
MC68HC908SR12•MC68HC08SR12 — Rev. 5.0
Freescale Semiconductor