BS85B12-3 HOLTEK [Holtek Semiconductor Inc], BS85B12-3 Datasheet - Page 27

• Manufacturer Part Number: BS85B12-3
• Description: Touch Key Flash Type 8-Bit MCU with LCD/LED Driver
• Manufacturer: HOLTEK [Holtek Semiconductor Inc]

BS85B12-3/BS85C20-3
Touch Key Flash MCU with LCD/LED Driver
Rev. 1.00
In Circuit Programming
Tempreg1 db ?
tempreg2 db ?
:
:
mov a,06h
mov tblp,a
mov a,07h
mov tbhp,a
:
:
tabrd tempreg1
dec tblp
tabrd tempreg2
:
:
org 700h
dc 00Ah, 00Bh, 00Ch, 00Dh, 00Eh, 00Fh, 01Ah, 01Bh
:
:
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.
The Holtek Flash MCU to Writer Programming Pin correspondence table is as follows:
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.
Holtek Writer
Pin Name
SDATA
SCLK
VPP
VDD
VSS
; temporary register #1
; temporary register #2
; initialise low table pointer - note that this address
; is referenced
; initialise high table pointer
; transfers value in table referenced by table pointer data at
; program memory address 706H 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 705H 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
Pin Name
Device
VDD
VSS
PA0
PA2
PA7
21
Serial Address and data -- read/write
Address and data serial clock input
Reset input
Power Supply (5.0V)
Ground
Pin Description
February 1, 2011