HT66FM5242 Datasheet, PDF (22/169 Pages) Holtek Semiconductor Inc – Brushless DC Motor Flash MCU

HT66FM5242
Brushless DC Motor Flash MCU
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 Writer Pins
ICPDA
ICPCK
VDD
VSS
MCU Programming Pins
PA0
PA2
VDD
VSS
Pin Description
Programming Serial Data/Address
Programming Clock
Power Supply
Ground
The Program Memory can 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 one line for the reset. The technical details
regarding the in-circuit programming of the device is beyond the scope of this document and will be
supplied in supplementary literature.
During the programming process, the user must take care of the ICPDA and ICPCK pins for data
and clock programming purposes to ensure that no other outputs are connected to these two pins.
W�ite� Connecto�
Signals
MCU P�og�amming
Pins
W�ite�_VDD
VDD
ICPDA
ICPCK
W�ite�_VSS
PA0
PA�
VSS
*
*
To othe� Ci�c�it
Note: * may be resistor or capacitor. The resistance of * must be greater than 1kΩ or the capacitance
of * must be less than 1nF.
Rev. 1.00
22
January 11, 2017