M68HC16 Z SERIES
REGISTER SUMMARY
USER’S MANUAL
D-59
D.7.8 MCCI Port Data Registers
Two registers are associated with port MCCI, the MCCI general-purpose I/O port. Pins
used for general-purpose I/O must be configured for that function. When using port
MCCI as an output port, after configuring the pins as I/O, write the first byte to be out-
put before writing to the MDDR. Afterwards, write to the MDDR to assign each I/O pin
as either input or output. This outputs the value contained in register PORTMC for all
pins defined as outputs. To output different data, write another byte to PORTMC.
Writes to PORTMC are stored in the internal data latch. If any bit of PORTMC is con-
figured as discrete output, the value latched for that bit is driven onto the pin. Reads
of PORTMC return the value of the pin only if the pin is configured as a discrete input.
Otherwise, the value read is the value of the latch.
Reads of PORTMCP always return the state of the pins regardless of whether the pins
are configured for input or output. Writes to PORTMCP have no effect.
D.7.9 SCI Control Register 0
SCCR0 contains the SCI baud rate selection field. Baud rate must be set before the
SCI is enabled. The CPU16 can read and write SCCR0 at any time. Changing the val-
ue of SCCR0 bits during a transfer operation can disrupt the transfer.
Bits [15:13] — Not Implemented
SCBR[12:0] — SCI Baud Rate
SCI baud rate is programmed by writing a 13-bit value to this field. Writing a value of
zero to SCBR disables the baud rate generator. Baud clock rate is calculated as fol-
lows:
PORTMC — MCCI Port Data Register
$YFFC0C
PORTMCP — MCCI Port Pin State Register
$YFFC0E
15
9
8
7
6
5
4
3
2
1
0
NOT USED
PMC7
PMC6
PMC5
PMC5
PMC4
PMC3
PMC2
PMC1
PMC0
RESET:
U
U
U
U
U
U
U
U
U
SCCR0A — SCIA Control Register 0
$YFFC18
SCCR0B — SCIB Control Register 0
$YFFC28
15
13
12
11
10
9
8
7
6
5
4
3
2
1
0
NOT USED
SCBR[12:0]
RESET:
0
0
0
0
0
0
0
0
0
0
1
0
0
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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