STC micro STC8A8K64D4 Series - Data Pointer Control Register (TA)

STC8A8K64D4 Series Manual
- 673 -
Instructions related to TSL include:
MOV DPTR,#data16
INC DPTR
MOVC A,@A+DPTR
MOVX A,@DPTR
MOVX @DPTR,A
AU1/AU0: Enable DPTR1 / DPTR0 Automatic increment / decrement control bit
0: disable Automatic increment / decrement function
1: enable Automatic increment / decrement function
Note: In write-protect mode, AU0 and AU1 can not be enabled individually. AU0 will be enabled
automatically if AU1 is enabled. If AU0 is enabled alone, there is no effect to AU1. To enable AU1 or AU0
independently, the TA register must be used to trigger the DPS protection mechanism. For more detail,
please refer to the description of the TA register. In addition, DPTR0 / DPTR1 will be incremented /
decremented automatically only after executing the following three instructions.
MOVC A,@A+DPTR
MOVX A,@DPTR
MOVX @DPTR,A
SEL: DPTR register select bit.
0: Default. DPTR0 is selected as current Data pointer.
1: DPTR1 is selected as current Data pointer.
The selection of current DPTR using SEL is valid for the following instructions,
MOV DPTR,#data16
INC DPTR
MOVC A,@A+DPTR
MOVX A,@DPTR
MOVX @DPTR,A
JMP @A+DPTR
24.1.4 Data Pointer control register (TA)
Symbol
Address
B7
B6
B5
B4
B3
B2
B1
B0
TA
AEH
AU1 and AU0 in the DPS register is write-protected by TA register. Since the program can not write AU1 and AU0 separately,
TA register must be used to trigger enabling AU1 or AU0 independently. TA is a write-only register.
The following steps must be executed if you need to enable AU1 or AU0 separately.
CLR EA ; disable interrupt (it is necessary to disable interrupt)
MOV TA,#0AAH ; write the trigger command sequence 1
; any other instructions can not be here
MOV TA,#55H ; write the trigger command sequence 2
; any other instructions can not be here
MOV DPS,#xxH ; Write-protection is temporarily disabled,
; and any value can be written to the DPS
; DSP enters the write-protected mode again
SETB EA ; enable interrupt if necessary