HT66F24D View Datasheet(PDF) - Holtek Semiconductor
Part Name
Description
MFG CO.
'HT66F24D' PDF : 177 Pages View PDF
A/D Flash Type 8-bit MCU with EEPROM
HT66F24D/HT66F25D
EEPROM Data Memory
The device contains an area of internal EEPROM Data Memory. EEPROM, which stands for
Electrically Erasable 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 information such as product
identification numbers, calibration 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 64x8 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 address and
data register in Bank 0 and a single control register in Bank 1.
Device
HT66F24D
HT66F25D
Capacity
64 x 8
64 x 8
EEPROM Data Memory Structure
Address
00H ~ 3FH
00H ~ 3FH
EEPROM Registers
Three registers control the overall operation of the internal EEPROM Data Memory. These are the
address register, 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 written to indirectly using the MP1 Memory Pointer and
Indirect 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 executed.
HT66F24D/HT66F25D EEPROM Register List
Bit
Name
7
6
5
4
3
2
1
0
EEA
—
—
D5
D4
D3
D2
D1
D0
EED
D7
D6
D5
D4
D3
D2
D1
D0
EEC
—
—
—
—
WREN
WR
RDEN
RD
EEA Register - HT66F24D/HT66F25D
Bit
7
6
5
4
3
2
1
0
Name
—
—
D5
D4
D3
D2
D1
D0
R/W
—
—
R/W
R/W
R/W
R/W
R/W
R/W
POR
—
—
0
0
0
0
0
0
Bit 7~6
Bit 5~0
“—” Unimplemented, read as 0
Data EEPROM address bit 5 ~ bit 0
Rev. 1.10
32
March 25, 2013
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