HC705P6AGRSSLASHD datasheet(84/134 Pages) NXP

84 / 134 page

EPROM

General Release Specification

MC68HC705P6A — Rev. 1.0

EPROM

10.3 EPROM Erasing

NOTE:

Only parts packaged in a windowed package may be erased. Others are

one-tme programmable and may not be erased by UV exposure.

The MC68HC705P6A can be erased by exposure to a high-intensity

ultraviolet (UV) light with a wavelength of 2537 angstroms. The

recommended dose (UV intensity multiplied by exposure time) is 15

Ws/cm2. UV lamps without shortwave filters should be used, and the

EPROM device should be positioned about one inch from the UV lamp.

An erased EPROM byte will read as $00.

10.4 EPROM Programming Sequence

The bootloader software goes through a complete write cycle of the

EPROM including the MOR. This is followed by a verify cycle which

continually branches in a loop if an error is found. A sample routine to

program a byte of EPROM is shown in Table 10-1.

NOTE:

To avoid damage to the MCU, VDD must be applied to the MCU before

VPP.

10.5 EPROM Registers

Three registers are associated with the EPROM: the EPROM

programming register (EPROG) and the two mask option registers

(MOR). The EPROG register controls the actual programming of the

EPROM bytes and the MOR. The MOR registers control the six mask

options found on the ROM version of this MCU (MC68HC05P6), the

EPROM security feature, and eight additional port A interrupt options.

10.6 EPROM Programming Register (EPROG)

This register is used to program the EPROM array. Only the ELAT and

EPGM bits are available. Table 10-1 shows the location of each bit in the

Freescale Semiconductor, Inc.

For More Information On This Product,

Go to: www.freescale.com

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