MC68HC711E20CFN4 Freescale Semiconductor, MC68HC711E20CFN4 Datasheet - Page 278

• Manufacturer Part Number: MC68HC711E20CFN4
• Description: IC MCU 20K OTP 4MHZ 52-PLCC
• Manufacturer: Freescale Semiconductor
• Series: HC11r

Specifications of MC68HC711E20CFN4

• Core Processor: HC11
• Core Size: 8-Bit
• Speed: 4MHz
• Connectivity: SCI, SPI
• Peripherals: POR, WDT
• Number Of I /o: 38
• Program Memory Size: 20KB (20K x 8)
• Program Memory Type: OTP
• Eeprom Size: 512 x 8
• Ram Size: 768 x 8
• Voltage - Supply (vcc/vdd): 4.5 V ~ 5.5 V
• Data Converters: A/D 8x8b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 52-PLCC
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Application Note
Basic Bootstrap Mode
278
Topics discussed in this application note include:
This section describes only basic functions of the bootstrap mode. Other
functions of the bootstrap mode are described in detail in the remainder
of this application note.
When an M68HC11 is reset in bootstrap mode, the reset vector is
fetched from a small internal read-only memory (ROM) called the
bootstrap ROM or boot ROM. The firmware program in this boot ROM
then controls the bootloading process, in this manner:
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Basic operation of the M68HC11 bootstrap mode
General discussion of bootstrap mode uses
Detailed explanation of on-chip bootstrap logic
Detailed explanation of bootstrap firmware
Bootstrap firmware vs. EEPROM security
Incorporating the bootstrap mode into a system
Driving bootstrap mode from another M68HC11
Driving bootstrap mode from a personal computer
Common bootstrap mode problems
Variations for specific versions of M68HC11
Commented listings for selected M68HC11 bootstrap ROMs
First, the on-chip SCI (serial communications interface) is
initialized. The first character received ($FF) determines which of
two possible baud rates should be used for the remaining
characters in the download operation.
Next, a binary program is received by the SCI system and is stored
in RAM.
Finally, a jump instruction is executed to pass control from the
bootloader firmware to the user’s loaded program.
AN1060 — Rev. 1.0
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