MC68HC908GT16 Datasheet, PDF (257/412 Pages) Motorola, Inc – Microcontrollers

Enhanced Serial Communications Interface (ESCI) Module
Functional Description
18.5.1 Data Format
The SCI uses the standard non-return-to-zero mark/space data format
illustrated in Figure 18-3.
START
BIT _{BIT 0}
BIT 1
BIT 2
8-BIT DATA FORMAT
(BIT M IN SCC1 CLEAR)
PARITY
OR DATA
BIT
BIT 3 BIT 4 BIT 5 BIT 6 BIT 7 STOP
BIT
NEXT
START
BIT
START
BIT BIT 0
BIT 1
BIT 2
9-BIT DATA FORMAT
(BIT M IN SCC1 SET)
BIT 3 BIT 4 BIT 5 BIT 6
PARITY
OR DATA
BIT
BIT 7 BIT 8 _STOP
BIT
NEXT
START
BIT
Figure 18-3. SCI Data Formats
18.5.2 Transmitter
Figure 18-4 shows the structure of the SCI transmitter and the registers
are summarized in Figure 18-2.
18.5.2.1 Character Length
The transmitter can accommodate either 8-bit or 9-bit data. The state of
the M bit in ESCI control register 1 (SCC1) determines character length.
When transmitting 9-bit data, bit T8 in ESCI control register 3 (SCC3) is
the ninth bit (bit 8).
18.5.2.2 Character Transmission
During an ESCI transmission, the transmit shift register shifts a
character out to the TxD pin. The ESCI data register (SCDR) is the write-
only buffer between the internal data bus and the transmit shift register.
MC68HC908GT16 • MC68HC908GT8 — Rev. 2
MOTOROLA
Enhanced Serial Communications Interface (ESCI) Module
Technical Data
257