MM912H634CM1AE Freescale Semiconductor, MM912H634CM1AE Datasheet - Page 191

• Manufacturer Part Number: MM912H634CM1AE
• Description: 64KS12 LIN2xLS/HS Isense
• Manufacturer: Freescale Semiconductor
• Series: -r

Specifications of MM912H634CM1AE

• Applications: Automotive
• Core Processor: HCS12
• Program Memory Type: FLASH (64 kB)
• Controller Series: HCS12
• Ram Size: 6K x 8
• Interface: LIN
• Number Of I /o: -
• Voltage - Supply: 5.5 V ~ 27 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 48-LQFP Exposed Pad
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

Figure 60
clock-cycle delay from the host-generated falling edge on BKGD to the start of the bit time as perceived by the target. The host
initiates the bit time but the target finishes it. Since the target wants the host to receive a logic 0, it drives the BKGD pin low for
13 target clock cycles then briefly drives it high to speed up the rising edge. The host samples the bit level about 10 target clock
cycles after starting the bit time.
4.31.4.7
BDM commands that require CPU execution are ultimately treated at the MCU bus rate. Since the BDM clock source can be
modified , it is very helpful to provide a handshake protocol in which the host could determine when an issued command is
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Start of Bit Time
Start of Bit Time
Speedup Pulse
Target System
Target System
(Target MCU)
(Target MCU)
BDM Clock
BDM Clock
BKGD Pin
BKGD Pin
Perceived
BKGD Pin
BKGD Pin
Drive and
Perceived
Speedup
Drive to
Drive to
shows the host receiving a logic 0 from the target. Since the host is asynchronous to the target, there is up to a one
Pulse
Host
Host
Serial Interface Hardware Handshake Protocol
High-Impedance
Figure 59. BDM Target-to-Host Serial Bit Timing (Logic 1)
Figure 60. BDM Target-to-Host Serial Bit Timing (Logic 0)
MM912_634 Advance Information, Rev. 4.0
10 Cycles
10 Cycles
R-C Rise
10 Cycles
10 Cycles
High-Impedance
Host Samples
High-Impedance
Host Samples
BKGD Pin
BKGD Pin
Speedup Pulse
High-Impedance
Next Bit
Earliest
Start of
Next Bit
Earliest
Start of
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