HC805K3GRSSLASHD datasheet(83/119 Pages) NXP

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General Release Specification

PEEPROM Registers

MC68HC805K3 — Rev. 1.0

Personality EEPROM

Table 9-1. Software to Read PEEPROM

pebsr

equ

$000e

pescr

equ

$000f

ram

equ

$000c

lda

#$xy

; xy is base addresses and should start on

sta

pebsr

; a first column (i.e., $00, $08, $10, $18, etc).

clr

ram

; clear ram location used for final result

peep_rd

rol

pescr

; c = pedata (c = carry bit)

ror

ram

; ram = c

inc

pebsr

; go to next bit in array.

brclr

0,pescr,peep_rd

; care data here, loop until all bytes read

; peep_rd loop ends when PEPCZF = 1.

; At end of loop, ram contains one row of PEEP data.

CPCLK — Charge Pump Clock Source

The CPCLK bit is a read/write bit that controls the source of the clock

for the charge pump. When the CPCLK bit is set, the charge pump is

driven by the PH2 bus clock. When the CPCLK bit is cleared, the

charge pump is driven from an internal ring oscillator. The CPCLK bit

is cleared when the device is in reset.

In systems where the desired PH2 clock rate is below 1 MHz, the

CPCLK bit should be cleared to enable the internal ring oscillator.

Otherwise, the charge pump does not attain sufficient program/erase

voltage because the clock source is too slow.

CPEN — Charge Pump Enable

The CPEN bit is a read/write bit to control the on-chip charge pump

for programming and erasure of the Personality EEPROM. This

charge pump is only intended for use at VDD supply voltages

above 3.0 Vdc. The charge pump is activated when both the CPEN

bit is set and one of the program or erase bits is also set (PEPGM,

PEBYTE, or PBULK). The charge pump supplies the required

programming voltage to the Personality EEPROM array. Once

activated, and after startup time tCP, the charge pump continues to

operate until all the program and erase bits are cleared.

NOTE:

If the personality EEPROM is read while the CPEN bit is set, the data is

unknown.

Freescale Semiconductor, Inc.

For More Information On This Product,

Go to: www.freescale.com

HC805K3GRS/D Datasheet(PDF) 83 Page - NXP Semiconductors

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