Rev. 1.50
��
����st ��� �01�
Rev. 1.50
�9
����st ��� �01�
HT66F0175/HT66F0185
A/D Flash MCU with EEPROM
HT66F0175/HT66F0185
A/D Flash MCU with EEPROM
Table Read Program Example
tempreg1 db ? ; temporary register #1
tempreg2 db ? ; temporary register #2
:
mov a,06h ; initialise low table pointer - note that this address is referenced
mov tblp,a ; to the last page or the page that tbhp pointed
mov a,0fh ; initialise high table pointer
mov tbhp,a
:
tabrd tempreg1 ; transfers value in table referenced by table pointer data at program
; memory address “0F06H” transferred to tempreg1 and TBLH
dec tblp ; reduce value of table pointer by one
tabrd tempreg2 ; transfers value in table referenced by table pointer data at program
; memory address “0F05H” transferred to tempreg2 and TBLH in this
; example the data “1AH” is transferred to tempreg1 and data “0FH” to
;
register
tempreg2
:
org 0F00h ; sets initial address of program memory
dc 00Ah, 00Bh, 00Ch, 00Dh, 00Eh, 00Fh, 01Ah, 01Bh
:
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
MCU Programming Pins
Pin Description
ICPD�
P�0
Pro�rammin� Serial Data/�ddress
ICPCK
P��
Pro�rammin� Clock
VDD
VDD
Power S�pply
VSS
VSS
Gro�nd
The Program Memory and EEPROM data 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. 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.
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.