MC68HC705P9 Datasheet, PDF (37/160 Pages) Motorola, Inc – HCMOS Microcontroller Unit

Freescale Semiconductor, Inc.
Memory
EPROM/OTPROM
3.6 EPROM/OTPROM
An MCU with a quartz window has 2104 bytes of erasable,
programmable ROM (EPROM). The quartz window allows EPROM
erasure with ultraviolet light.
NOTE: Keep the quartz window covered with an opaque material except when
programming the MCU. Ambient light may affect MCU operation.
In an MCU without the quartz window, the EPROM cannot be erased
and serves as 2104 bytes of one-time programmable ROM (OTPROM).
The following addresses are user EPROM/OTPROM locations:
• $0020–$004F
• $0100–$08FF
• $1FF8–$1FFF (reserved for user-defined interrupt and reset
vectors)
The mask option register (MOR) is an EPROM/OTPROM location at
address $0900.
3.6.1 EPROM/OTPROM Programming
The two ways to program the EPROM/OTPROM are:
• Manipulating the control bits in the EPROM programming register
to program the EPROM/OTPROM on a byte-by-byte basis
• Activating the bootloader ROM to download the contents of an
external memory device to the on-chip EPROM/OTPROM
MC68HC705P9 — Rev. 4.0
MOTOROLA
Memory
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Technical Data
37