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
In Circuit Programming – ICP
The provision of Flash type Program Memory provides the user with a means of convenient and easy
upgrades and modifications to their programs on the same device. As an additional convenience,
Holtek has provided a means of programming the microcontroller in-circuit using a 4-pin interface.
This provides manufacturers with the possibility of manufacturing their circuit boards complete with
a programmed or un-programmed microcontroller, and then programming or upgrading the program
at a later stage. This enables product manufacturers to easily keep their manufactured products
supplied with the latest program releases without removal and re-insertion of the device.
Holtek
Write Pins
MCU Programming Pins
Function
HT66F002/HT66F0025
HT66F003/HT66F004
ICPDA
PA0
Programming Serial Data
ICPCK
PA7
PA2
Programming Serial Clock
VDD
VDD
Power Supply
VSS
VSS
Ground
The Program Memory and EEPROM data memory can both be programmed serially in-circuit using
this 4-wire interface. Data is downloaded and uploaded serially on a single pin with an additional
line for the clock. Two additional lines are required for the power supply and ground. The technical
details regarding the in-circuit programming of the device are beyond the scope of this document
and will be supplied in supplementary literature.
HT66F002/HT66F0025
*
*
Writer_VDD
ICPDA
ICPCK
Writer_VSS
To other Circuit
VDD
PA0
PA7
VSS
Writer Connector
Signals
MCU Programming
Pins
HT66F003/HT66F004
*
*
Writer_VDD
ICPDA
ICPCK
Writer_VSS
To other Circuit
VDD
PA0
PA2
VSS
Writer Connector
Signals
MCU Programming
Pins
Note: * may be resistor or capacitor. The resistance of * must be greater than 1k or the capacitance of * must be
less than 1nF.
On-Chip Debug Support – OCDS
There is
an
EV chip which is used to emulate the HT66F00x device series. This EV chip device
also provides an “On-Chip Debug” function to debug the device during the development process.
The EV chip and the actual MCU devices are almost functionally compatible except for the “On-
Chip Debug” function. Users can use the EV chip device to emulate the real chip device behavior
by connecting the OCDSDA and OCDSCK pins to the Holtek HT-IDE development tools. The
OCDSDA pin is the OCDS Data/Address input/output pin while the OCDSCK pin is the OCDS
clock input pin. When users use the EV chip for debugging, other functions which are shared with
the OCDSDA and OCDSCK pins in the actual MCU device will have no effect in the EV chip.
However, the two OCDS pins which are pin-shared with the ICP programming pins are still used as
the Flash Memory programming pins for ICP. For a more detailed OCDS description, refer to the
corresponding document named “Holtek e-Link for 8-bit MCU OCDS User’s Guide”.
