MC68HC12 MOTOROLA [Motorola, Inc], MC68HC12 Datasheet - Page 399

• Manufacturer Part Number: MC68HC12
• Description: The MC68HC912DT128A microcontroller unit (MCU) is a 16-bit device composed of standard on-chip peripherals including a 16-bit central processing unit
• Manufacturer: MOTOROLA [Motorola, Inc]

MC68HC912DT128A — Rev 4.0
MOTOROLA
TRANSMIT 1
(TARGET MCU)
TRANSMIT 0
OF BIT TIME
PERCEIVED
BKGD PIN
SPEEDUP PULSE
BKGD PIN
DRIVE TO
(TARGET
BDMCLK
BDMCLK
TARGET MCU
HOST
HOST
START
MCU)
HOST
START OF BIT
PERCEIVED
SYNCHRONIZATION
UNCERTAINTY
TIME
Figure 20-2. BDM Target to Host Serial Bit Timing (Logic 1)
Figure 20-1. BDM Host to Target Serial Bit Timing
HIGH-IMPEDANCE
BKGD pin during host-to-target transmissions to 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
Background Debug Mode
HC12A4 BDM TARGET TO HOST TIM 1
Development Support
HC12A4 BDM HOST TO TARGET TIM
EARLIEST
START OF
EARLIEST
START OF
Technical Data
NEXT BIT
NEXT BIT
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