MC912DG128A Motorola, MC912DG128A Datasheet - Page 331

• Manufacturer Part Number: MC912DG128A
• Description: Microcontrollers
• Manufacturer: Motorola

5-dev
MOTOROLA
(TARGET MCU)
TRANSMIT 1
TRANSMIT 0
OF BIT TIME
PERCEIVED
BKGD PIN
BKGD PIN
DRIVE TO
SPEEDUP PULSE
(TARGET
TARGET MCU
HOST
START
HOST
BCLK
MCU)
HOST
START OF BIT
BCLK
PERCEIVED
SYNCHRONIZATION
UNCERTAINTY
TIME
Figure 60 BDM Target to Host Serial Bit Timing (Logic 1)
Figure 59 BDM Host to Target Serial Bit Timing
HIGH-IMPEDANCE
speed up rising edges. Since the target does not drive the BKGD pin
during this period, there is no need to treat the line as an open-drain
signal during host-to-target transmissions.
10 CYCLES
R-C RISE
10 CYCLES
10 CYCLES
Development Support
TARGET SENSES BIT
HIGH-IMPEDANCE
HOST SAMPLES
BKGD PIN
HIGH-IMPEDANCE
MC68HC912DT128A Rev 2.0
Background Debug Mode
HC12A4 BDM TARGET TO HOST TIM 1
Development Support
HC12A4 BDM HOST TO TARGET TIM
EARLIEST
START OF
START OF
EARLIEST
NEXT BIT
NEXT BIT
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