Miscellaneous Register - Motorola DragonBall MC68328 User Manual

UART
DATA
These bits are the parallel transmit-data inputs. While in 7-bit mode, D7 is ignored. While
in 8-bit mode, all bits are used. Data is transmitted LSB first. A new character is transmit-
ted when these bits are written. These bits read as 0.

8.2.9 Miscellaneous Register

This register contains miscellaneous bits to control test features of the UART block. Some
bits are intended for factory use only and should not be disturbed by users.
15 14 13 12
CLK FORCE
RSVD LOOP
SRC PERR
ADDRESS: $(FF)FFF908
RSVD
These bits are reserved and should remain 0.
CLK SRC
This bit selects the source of the 1x bit clock for transmit and receive. While high, the bit
clock is derived directly from the GPIO pin (it must be configured as an input.) While low,
(normal) the bit clock is supplied by the baud generator. This bit allows high-speed syn-
chronous applications where a clock is provided by the external system.
0 = Bit clock generated by baud generator
1 = Bit clock supplied from GPIO (input)
FORCE PERR
While high, this bit forces the transmitter to generate parity errors if parity is enabled. This
bit is provided for system debugging.
0 = Generate normal parity
1 = Generate inverted parity (error)
LOOP
This bit controls loopback for system-test purposes. While this bit is high, the receiver in-
put is internally connected to the transmitter and ignores the RXD pin. The transmitter is
unaffected by this bit. The receiver can be in either clock mode (16x or 1x) for proper op-
eration.
0 = Normal receiver operation
1 = Internally connect transmitter output to receiver input
RTS CONT
This bit selects the function of the RTS pin.
0 = RTS pin is controlled by the RTS bit
1 = RTS pin is controlled by the receiver FIFO. When the FIFO is full (one slot remain-
ing) RTS is negated.
8-12 MC68328 DRAGONBALL PROCESSOR USER'S MANUAL
11 10 9
RSVD
Figure 8-6. Miscellaneous Register
RTS Control
8 7 6 5
RTS IRDA
RTS
CONT ENABLE
4 3 2 1
IRDA
UNUSED
LOOP
Reset Value: $0000
MOTOROLA
0