Digi NS9215 - Manual (Page 389)

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S E R I A L C O N T R O L M O D U L E : U A R T
ARM wakeup on character recognition
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character completes, regardless of any flow control mechanism that might stall
normal data transmission.
Use the Force Transmit Character Control register to program this operation.
Force character
transmission
procedure
These steps outline a single force character transmission operation:
1
Read the Force Transmit Character Control register and verify that the ENABLE
field is 0. The Force Transmit Character Control register must not be written
while the ENABLE field is 1.
2
Write a 1 to the ENABLE field and the required character to the CHAR field. This
operation can be a single step.
Collecting
feedback
Force character transmission completion status is available. It is up to you as to
whether you want to collect feedback. If you do want to collect feedback, these are
your options:
Poll the ENABLE field in the Force Transmit Character Control register until it
reads 0.
Poll the FORCE field in the Interrupt Status register until it reads 1.
Enable the FORCE interrupt by writing a 1 to the FORCE field in the Interrupt
Enable register and servicing the interrupt when it occurs.
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A R M w a k e u p o n c h a r a c t e r r e c o g n i t i o n
The UART module provides a signal to the SCM module that can wake up the ARM
processor. This signal is asserted when a specified character is received. Use the
Receive Character Match Control registers and the ARM Wakeup Control register to
implement the logic.
Example
configuration
This table shows a sample configuration where the wakeup signal is asserted on
reception of any character:
Control register Field Value Comment
Receive Character Match Control
Register 0 ENABLE 1 Enable character match
MASK 0xff Mask all bits
DATA 0x00 Don’t care
ARM Wakeup Control register ENABLE 1 Enable the function