HT68F04 Holtek Semiconductor, HT68F04 Datasheet - Page 23

• Manufacturer Part Number: HT68F04
• Description: Small Package Enhanced Flash Type 8-Bit MCU
• Manufacturer: Holtek Semiconductor

EEPROM Data Memory
The device contains an area of internal EEPROM Data
Memory. EEPROM, which stands for Electrically Eras-
able Programmable Read Only Memory, is by its nature
a non-volatile form of re-programmable memory, with
data retention even when its power supply is removed.
By incorporating this kind of data memory, a whole new
host of application possibilities are made available to the
designer. The availability of EEPROM storage allows in-
formation such as product identification numbers, cali-
bration values, specific user data, system setup data or
other product information to be stored directly within the
product microcontroller. The process of reading and
writing data to the EEPROM memory has been reduced
to a very trivial affair.
EEPROM Data Memory Structure
The EEPROM Data Memory capacity is 64´8 bits for
this series of devices. Unlike the Program Memory and
RAM Data Memory, the EEPROM Data Memory is not
directly mapped into memory space and is therefore not
directly addressable in the same way as the other types
of memory. Read and Write operations to the EEPROM
are carried out in single byte operations using an ad-
dress and data register in Bank 0 and a single control
register in Bank 1.
·
·
Rev. 1.00
EEPROM Register List
EEA Register
Bit 7 ~ 6
Bit 5 ~ 0
EEA
EED
EEC
Name
Name
POR
R/W
Bit
Unimplemented, read as ²0²
Data EEPROM address
Data EEPROM address bit 5 ~ bit 0
D7
¾
¾
¾
¾
¾
7
7
D6
¾
¾
¾
¾
¾
6
6
R/W
D5
D5
D5
¾
5
5
x
HT66F03/HT66F04/HT68F03/HT68F04
23
R/W
D4
D4
D4
¾
4
4
x
EEPROM Registers
Three registers control the overall operation of the inter-
nal EEPROM Data Memory. These are the address reg-
ister, EEA, the data register, EED and a single control
register, EEC. As both the EEA and EED registers are
located in Bank 0, they can be directly accessed in the
same was as any other Special Function Register. The
EEC register however, being located in Bank1, cannot
be addressed directly and can only be read from or writ-
ten to indirectly using the MP1 Memory Pointer and Indi-
rect Addressing Register, IAR1. Because the EEC
control register is located at address 40H in Bank 1, the
MP1 Memory Pointer must first be set to the value 40H
and the Bank Pointer register, BP, set to the value, 01H,
before any operations on the EEC register are exe-
cuted.
All devices
Bit
WREN
R/W
Device
D3
D3
D3
3
3
x
R/W
WR
D2
D2
D2
2
2
x
Capacity
64´8
RDEN
R/W
D1
D1
D1
1
1
x
April 16, 2010
00H ~ 3FH
Address
²x² unknown
www.DataSheet4U.com
R/W
RD
D0
D0
D0
0
0
x