HT68F14 HOLTEK [Holtek Semiconductor Inc], HT68F14 Datasheet - Page 21

• Manufacturer Part Number: HT68F14
• Description: Enhanced I/O Flash Type MCU
• Manufacturer: HOLTEK [Holtek Semiconductor Inc]

HT68F13/HT68F14/HT68F15
Enhanced I/O Flash Type MCU
Rev. 1.10
In Circuit Programming
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 5-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.
The Holtek Flash MCU to Writer Programming Pin correspondence table is as follows:
The Program Memory can be programmed serially in-circuit using this 5-wire interface. Data is
downloaded and uploaded serially on a single pin with an additional line for the clock. Two addi-
tional lines are required for the power supply and one line for the reset. The technical details regard-
ing the in-circuit programming of the devices are beyond the scope of this document and will be
supplied in supplementary literature.
During the programming process the RES pin will be held low by the programmer disabling the
normal operation of the microcontroller and taking control of the PA0 and PA2 I/O pins for data and
clock programming purposes. The user must there take care to ensure that no other outputs are
connected to these two pins.
Note:
Holtek Writer
Pin Name
SDATA
SCLK
VPP
VDD
VSS
* may be resistor or capacitor. The resistance of * must be greater than 1kW or the capacitance
of * must be less than 1nF.
Pin Name
Devices
VDD
RES
VSS
PA0
PA2
21
Serial Address and data -- read/write
Address and data serial clock input
Reset input
Power Supply (5.0V)
Ground
Pin Description
February 9, 2011