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Rev. 1.21
22
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Rev. 1.21
23
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HT66F488/HT66F489
A/D Flash MCU with EEPROM
HT66F488/HT66F489
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
:
:
tabrdl tempreg1 ; transfers value in table referenced by table pointer data at program
; memory address “F06H” transferred to tempreg1 and TBLH
dec tblp ; reduce value of table pointer by one
tabrdl tempreg2 ; transfers value in table referenced by table pointer
;
data
at
program
memory
address
“F05H”
transferred
to
;
tempreg2
and
TBLH
; in this example the data “1AH” is transferred to tempreg1 and data “0FH”
;
to
register
tempreg2
:
:
org
F00h
;
sets
initial
address
of
program
memory
dc 00Ah, 00Bh, 00Ch, 00Dh, 00Eh, 00Fh, 01Ah, 01Bh
:
:
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 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.
The Holtek Flash MCU to Writer Programming Pin correspondence table is as follows:
Holtek Write Pins
MCU Programming Pins
Function
ICPDA
PD�
P�og�a��ing Se�ial Data
ICPCK
PB4
P�og�a��ing Se�ial Clock
VDD
VDD
Powe� Supply
VSS
VSS
G�ound
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.
During the programming process, the user must take care to ensure that no other outputs are
connected to the PD0 and PB4 pins.