MC68HC908KX2 MOTOROLA [Motorola, Inc], MC68HC908KX2 Datasheet - Page 194

• Manufacturer Part Number: MC68HC908KX2
• Description: Microcontrollers
• Manufacturer: MOTOROLA [Motorola, Inc]

Serial Communications Interface Module (SCI)
14.5.3.6 Receiver Wakeup
Technical Data
194
So that the MCU can ignore transmissions intended only for other
receivers in multiple-receiver systems, the receiver can be put into a
standby state. Setting the receiver wakeup bit, RWU, in SCC2 puts the
receiver into a standby state during which receiver interrupts are
disabled.
Depending on the state of the WAKE bit in SCC1, either of two
conditions on the RxD pin can bring the receiver out of the standby state:
1. Address mark — An address mark is a logic 1 in the most
With the misaligned character shown in
counts 154 RT cycles at the point when the count of the transmitting
device is 10 bit times
The maximum percent difference between the receiver count and the
transmitter count of a fast 8-bit character with no errors is
For a 9-bit character, data sampling of the stop bit takes the receiver
10 bit times
With the misaligned character shown in
counts 170 RT cycles at the point when the count of the transmitting
device is 11 bit times
The maximum percent difference between the receiver count and the
transmitter count of a fast 9-bit character with no errors is
Serial Communications Interface Module (SCI)
significant bit position of a received character. When the WAKE bit
is set, an address mark wakes the receiver from the standby state
by clearing the RWU bit. The address mark also sets the SCI
receiver full bit, SCRF. Software can then compare the character
containing the address mark to the user-defined address of the
receiver. If they are the same, the receiver remains awake and
processes the characters that follow. If they are not the same,
MC68HC908KX8 • MC68HC908KX2 • MC68HC08KX8 — Rev. 1.0
16 RT cycles + 10 RT cycles = 170 RT cycles.
154 160
------------------------- -
170 176
------------------------- -
154
170
16 RT cycles = 160 RT cycles.
16 RT cycles = 176 RT cycles.
–
–
100
100
=
=
3.90%.
3.53%.
Figure
Figure
14-8, the receiver
14-8, the receiver
MOTOROLA