Rev. 1.71
24
April 11, 2017
Rev. 1.71
25
April 11, 2017
HT66F002/HT66F0025/HT66F003/HT66F004
Cost-Effective A/D Flash MCU with EEPROM
HT66F002/HT66F0025/HT66F003/HT66F004
Cost-Effective A/D Flash MCU with EEPROM
Holtek e-Link Pins
EV Chip Pins
Pin Description
OCDSDA
OCDSDA
On-chip Debug Support Data/Address input/output
OCDSCK
OCDSCK
On-chip Debug Support Clock input
VDD
VDD
Power Supply
GND
VSS
Ground
RAM Data Memory
The Data Memory is a volatile area of 8-bit wide RAM internal memory and is the location where
temporary information is stored.
Structure
Divided into two sections, the first of these is an area of RAM, known as the Special Function Data
Memory. Here are located registers which are necessary for correct operation of the device. Many
of these registers can be read from and written to directly under program control, however, some
remain protected from user manipulation. The second area of Data Memory is known as the General
Purpose Data Memory, which is reserved for general purpose use. All locations within this area are
read and write accessible under program control.
The overall Data Memory is subdivided into two banks. The Special Purpose Data Memory registers
are accessible in all banks, with the exception of the EEC register at address
40H, which is only
accessible in Bank 1. Switching between the different Data Memory banks is achieved by setting the
Bank Pointer to the correct value. The start address of the Data Memory for all devices is the address
00H.
General Purpose Data Memory
There is 64 or 96 bytes of general purpose data memory which are arranged in Bank 0 and Bank1.
All microcontroller programs require an area of read/write memory where temporary data can be
stored and retrieved for use later. It is this area of RAM memory that is known as General Purpose
Data Memory. This area of Data Memory is fully accessible by the user programing for both reading
and writing operations. By using the bit operation instructions individual bits can be set or reset
under program control giving the user a large range of flexibility for bit manipulation in the Data
Memory.
Special Purpose Data Memory
This area of Data Memory is where registers, necessary for the correct operation of the
microcontroller, are stored. Most of the registers are both readable and writeable but some are
protected and are readable only, the details of which are located under the relevant Special Function
Register section. Note that for locations that are unused, any read instruction to these addresses will
return the value “00H”.
Device
Capacity Bank 0
Bank 1
HT66F002/HT66F0025/HT66F003
64×8
40H~7FH 40H EEC register only
HT66F004
96×8
40H~9FH 40H EEC register only
