MC68HC705E6CDW 데이터 시트보기 (PDF) - Freescale Semiconductor
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MC68HC705E6CDW Datasheet PDF : 140 Pages
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Freescale Semiconductor, Inc.
Modes of Operation and Pin Descriptions
Bootloader
functions
The bootloader code deals with the copying of user code from an
external EPROM into the on-chip EPROM. The bootloader function can
only be used with an external EPROM. The bootloader performs a
programming pass followed by a verify pass.
Two pins, PC0 and PC1, are used to drive the PROG and VERF LED
outputs. While the EPROM is being programmed, the PROG LED lights
up; when programming is complete, the internal EPROM contents are
compared to that of the external EPROM and, if they match exactly, the
VERF LED lights up.
The EPROM must be in the erased state before performing a program
cycle. The erased state of the EPROM is $00.
EPROM
programming
instructions
NOTE:
The following procedure should be carried out when programming the
EPROM. In order to prevent damage to the device, VDD should always be
applied to the part before VPP when applying power. Similarly, VPP should
be removed from the part before VDD when switching the power off.
1. Turn off power to the circuit.
2. Install the MCU and the EPROM.
3. Select the bootloader function:
Program 1 byte: Open S1 and S2 and close S3.
Program 4 bytes: Open S1, S2 and S3.
Verify only: Open S1 and S3 and close S2.
4. Close switch S4 to hold the MCU in reset.
5. Apply VDD to the circuit.
6. Apply the EPROM programming voltage (VPP) to the circuit.
7. Open switch S4 to take the MCU out of reset.
During programming the PROG LED turns on and is switched off
when the verification routine begins. If verification is successful,
the VERF LED turns on. If the bootloader finds an error during
verification, it puts the error address on the external address bus
and stops running.
8. Close switch S4 to hold the MCU in reset.
9. Remove the VPP voltage.
10. Remove the VDD voltage.
EPROM programming must be carried out at room temperature.
MC68HC05E6 — Rev. 1.0
4-pin
Modes of Operation and Pin Descriptions
For More Information On This Product,
Go to: www.freescale.com
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