Datasheet

UART Modules
12-24 MCF5206e USER’S MANUAL MOTOROLA
12.4.1.4 CLOCK-SELECT REGISTER (UCSR). The UCSR selects the internal clock
(timer mode) or the external clock in synchronous or asynchronous mode. To use the
timer mode for either the receiver and transmitter channel, program the UCSR to the value
$DD. The transmitter and receiver can be programmed to different clock sources.
RCS3–RCS0 — Receiver Clock Select
These bits select the clock source for the receiver channel. Table 12-6 details the register
bits necessary for each mode.
TCS3–TCS0 — Transmitter Clock Select
These bits determine the clock source of the UART transmitter channel.
12.4.1.5 COMMAND REGISTER (UCR). The UCR supplies commands to the UART.
You can specify multiple commands in a single write to the UCR if the commands are not
conflicting – e.g., reset-transmitter and enable-transmitter commands cannot be specified
in a single command.
UCSR MBAR + $184
7 6 5 4 3 2 1 0
RCS3 RCS2 RCS1 RCS0 TCS3 TCS2 TCS1 TCS0
RESET:
1 1 0 1 1 1 0 1
WRITE ONLY SUPERVISOR OR USER
Table 12-6. RCSx Control Bits
RCS3 RCS2 RCS1 RCS0 MODE
1 101 TIMER
1 1 1 0 Ext. clk. x 16
1 1 1 1 Ext. clk. x 1
Table 12-7. TCSx Control Bits
TCS3 TCS2 TCS1 TCS0 SET 1
1 101TIMER
1 1 1 0 Ext. clk. x 16
1 1 1 1 Ext. clk. x 1
UCR MBAR + $188
7 6 5 4 3 2 1 0
— MISC2 MISC1 MISC0 TC1 TC0 RC1 RC0
RESET:
0 0 0 0 0 0 0 0
WRITE ONLY SUPERVISOR OR USER
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Freescale Semiconductor, Inc.
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