MC68HC05C5 View Datasheet(PDF) - Freescale Semiconductor

Part Name

Description

Manufacturer

MC68HC05C5

SPECIFICATION (General Release)

Freescale Semiconductor 

Freescale SemicondMuCc6t8oHrC,0I5nCc5.Specification Rev. 1.2

address and data buses are configured for normal operation. LATCH is automatically

cleared when LVPI is set. Reset clears this bit.

3.3.1.5

EERC - EEPROM RC Oscillator Control

When this bit is set, the EEPROM section uses the internal RC oscillator instead of the

CPU clock. After setting the EERC bit, delay a time tRCON to allow the RC oscillator to

stabilize. This bit is readable and writable and should be set by the user when the internal

bus frequency falls below 1.5 MHz. EERC is automatically cleared when LVPI is set.

Reset clears this bit.

3.3.1.6

EEPGM - EEPROM Programming Power Enable

EEPGM must be written to enable (or disable) the EEPGM function. When set, EEPGM

turns on the charge pump and enables the programming (or erasing) power to the

EEPROM array. When clear, this power is switched off. This will enable pulsing of the

programming voltage to be controlled internally. This bit can be read at any time, but can

only be written to if LATCH = 1. If LATCH is not set, then EEPGM cannot be set. LATCH

and EEPGM can not both be set with one write if LATCH is cleared. EEPGM is

automatically cleared when LVPI is set. EEPGM is automatically cleared when LATCH is

cleared. Reset clears this bit.

3.3.2 PROGRAMMING/ERASING PROCEDURES

To program a byte of EEPROM, set LATCH = CPEN = 1, set ER1 = ER0 = 0, write data

to the desired address and then set EEPGM for a time tEPGM.

NOTE:

Any bit should be erased before it is programmed. However, if write/

erase cycling is a concern, a procedure can be followed to minimize

the cycling of each bit in each EEPROM byte. Here is the procedure:

• If PB•EB* = 0, then program the new data over the existing data

without erasing it first

• If PB•EB* ≠ 0, then erase byte before programming

• Where PB = Byte data to be programmed

and EB = Existing EEPROM byte data.

Section 3: Memory

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