Rev. 1.10
22
November 04, 2019
Rev. 1.10
23
November 04, 2019
HT45F5Q-3
Battery Charger Flash MCU
HT45F5Q-3
Battery Charger Flash MCU
address pointed by the TBLP and TBHP registers if the “TABRD [m]” instruction is being used. The
high byte of the table data which in this case is equal to zero will be transferred to the TBLH register
automatically when the “TABRD [m]” instruction is executed.
Because the TBLH register is a read-only register and cannot be restored, care should be taken
to ensure its protection if both the main routine and Interrupt Service Routine use table read
instructions. If using the table read instructions, the Interrupt Service Routines may change the
value of the TBLH and subsequently cause errors if used again by the main routine. As a rule it is
recommended that simultaneous use of the table read instructions should be avoided. However, in
situations where simultaneous use cannot be avoided, the interrupts should be disabled prior to the
execution of any main routine table-read instructions. Note that all table related instructions require
two instruction cycles to complete their operation.
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 ; it is not necessary to set tbhp if executing tabrdl
:
:
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 tempreg2
;
the
value
“
00H
”
will be transferred to the high byte register TBLH
:
:
org 0F00h
; set initial address of last page
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
ICPDA
PA0
Programming Serial Data/Address
ICPCK
PA2
Programming Clock
VDD
VDD
Power Supply
VSS
VSS
Ground
