16-24
MCF5272 User’s Manual
Operation
If the clear-to-send operation is enabled, CTS must be asserted for the character to be
transmitted. If CTS is negated in the middle of a transmission, the character in the shift
register is sent and TxD remains in mark state until CTS is reasserted. If the transmitter is
forced to send a continuous low condition by issuing a
START
BREAK
command, the
transmitter ignores the state of CTS.
If the transmitter is programmed to automatically negate RTS when a message transmission
completes, RTS must be asserted manually before a message is sent. In applications in
which the transmitter is disabled after transmission is complete and RTS is appropriately
programmed, RTS is negated one bit time after the character in the shift register is
completely transmitted. The transmitter must be manually reenabled by reasserting RTS
before the next message is to be sent.
The transmitter must be enabled prior to accepting a
START
BREAK
command. If the
transmitter is disabled while the BREAK is active, the BREAK is not terminated. The
BREAK can only be terminated by using the
STOP
BREAK
command.
Figure 16-25 shows the functional timing information for the transmitter.
Figure 16-25. Transmitter Timing
C1
1
C2
C3
Break
C4
C6
TxD
Transmitter
Enabled
USRn[TxRDY]
W
2
W
W
W
W
W
W
W
CTS
3
RTS
4
Manually asserted
by
BIT
-
SET
command
Manually
asserted
Start
break
C5
not
transmitted
C6
C4
Stop
break
C3
C2
C1
1
C1 in transmission
3
UMR2n[TxCTS] = 1
1
Cn = transmit characters
2
W = write
4
UMR2n[TxRTS] = 1
internal
module
select
Содержание DigitalDNA ColdFire MCF5272
Страница 1: ...MCF5272UM D Rev 0 02 2001 MCF5272 ColdFire Integrated Microprocessor User s Manual ...
Страница 38: ...xxxviii MCF5272 User s Manual TABLES Table Number Title Page Number ...
Страница 58: ...1 10 MCF5272 User s Manual MCF5272 Specific Features ...
Страница 90: ...2 42 MCF5272 User s Manual Exception Processing Overview ...
Страница 96: ...3 6 MCF5272 User s Manual MAC Instruction Execution Timings ...
Страница 158: ...5 46 MCF5272 User s Manual Motorola Recommended BDM Pinout ...
Страница 184: ...7 12 MCF5272 User s Manual Interrupt Controller Registers ...
Страница 338: ...13 44 MCF5272 User s Manual Application Examples ...
Страница 414: ...18 6 MCF5272 User s Manual PWM Programming Model ...
Страница 452: ...19 38 MCF5272 User s Manual Power Supply Pins ...
Страница 482: ...20 30 MCF5272 User s Manual Reset Operation ...
Страница 492: ...21 10 MCF5272 User s Manual Non IEEE 1149 1 Operation ...
Страница 548: ...INDEX Index 12 MCF5272 User s Manual ...