mc68hc916y3 Freescale Semiconductor, Inc, mc68hc916y3 Datasheet - Page 264

• Manufacturer Part Number: mc68hc916y3
• Description: Mc68hc16y3 16 Bit Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

11.4.3.9 Internal Loop Mode
11-32
MOTOROLA
Address-mark wake-up uses a special frame format to wake up the receiver. When the
MSB of an address-mark frame is set, that frame contains address information. The
first frame of each transmission must be an address frame. When the MSB of a frame
is set, the receiver clears RWU and wakes up. The byte is received normally, trans-
ferred to the RDR, and the RDRF flag is set. If software does not recognize the ad-
dress, it can set RWU and put the receiver back to sleep. Address-mark wake-up
allows idle time between frames and eliminates idle time between transmissions. How-
ever, there is a loss of efficiency because of an additional bit-time per frame.
The LOOPS bit in SCCR1 controls a feedback path in the data serial shifter. When
LOOPS is set, the SCI transmitter output is fed back into the receive serial shifter. TXD
is asserted (idle line). Both transmitter and receiver must be enabled before entering
loop mode.
Freescale Semiconductor, Inc.
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MC68HC16Y3/916Y3
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