In Ci�Cuit P�Og�A - Holtek HT66F488 Manual

HT66F488/HT66F489
A/D Flash MCU with EEPROM
Table Read Program Example
tempreg1 db ?
tempreg2 db ?
:
:
mov a,06h
mov tblp,a
:
:
tabrdl tempreg1
dec tblp
tabrdl tempreg2
:
:
org F00h
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
ICPDA
ICPCK
VDD
VSS
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.
Rev. 1.21
; temporary register #1
; temporary register #2
; initialise low table pointer - note that this address is referenced
; to the last page
; transfers value in table referenced by table pointer data at program
; memory address "F06H" transferred to tempreg1 and TBLH
; reduce value of table pointer by one
; 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
; sets initial address of program memory
MCU Programming Pins
PD�
PB4
VDD
VSS
23
Function
P�og�a��ing Se�ial Data
P�og�a��ing Se�ial Clock
Powe� Supply
G�ound
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