HT45F23 datasheet(26/152 Pages) HOLTEK

26 / 152 page

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.

MCU Programming Pins

Function

PA0

Serial Data Input/Output

PA2

Serial Clock

RES

Device Reset

VDD

Power Supply

VSS

Ground

The Program Memory and EEPROM data memory can both 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 additional lines are required for the power supply and one line for the reset.

The technical details regarding 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.

Programmer Pin

MCU Pins

RES

PB6

DATA

PA0

CLK

PA2

Programmer and MCU Pins

Rev. 1.20

September 15, 2011

HT45F23/HT45F43

8-Bit Flash MCU with Op Amps & Comparators

W r i t e r _ V D D

R E S

D A T A

C L K

W r i t e r _ V S S

T o o t h e r C i r c u i t

D A T A

C L K

V S S

R E S

V D D

W r i t e r C o n n e c t o r

S i g n a l s

M C U P r o g r a m m i n g

P i n s

Note:

* may be resistor or capacitor. The resistance of * must be greater than 1k

W or the capacitance

of * must be less than 1nF.

HT45F23 Datasheet(PDF) 26 Page - Holtek Semiconductor Inc

HT45F23 Datasheet(HTML) 26 Page - Holtek Semiconductor Inc

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