ht82k70e-l Holtek Semiconductor Inc., ht82k70e-l Datasheet - Page 10

• Manufacturer Part Number: ht82k70e-l
• Description: I/o Type 8-bit Otp Mcu
• Manufacturer: Holtek Semiconductor Inc.

tempreg1 db
tempreg2 db
mov a,06h
mov tblp,a
tabrdl
dec tblp
tabrdl
org 1F00h
dc
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 the table read instructions. If using the table read instructions,
the Interrupt Service Routines may change the value of 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.
Rev. 1.00
Table Read Program Example
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:
:
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00Ah, 00Bh, 00Ch, 00Dh, 00Eh, 00Fh, 01Ah, 01Bh
:
:
tempreg1
tempreg2
?
?
; temporary register #1
; temporary register #2
; initialise table pointer - note that this address
; is referenced
; to the last page or present page
; transfers value in table referenced by table pointer
; to tempregl
; data at prog. memory address 1F06H transferred to
; tempreg1 and TBLH
; reduce value of table pointer by one
; transfers value in table referenced by table pointer
; to tempreg2
; data at prog.memory address 1F05H transferred to
; tempreg2 and TBLH
; in this example the data 1AH is transferred to
; tempreg1 and data 0FH to register tempreg2
; the value 00H will be transferred to the high byte
; register TBLH
; sets initial address of last page
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HT82K70E-L/HT82K76E-L
September 15, 2009