BS83A02A-4 Datasheet, PDF (16/81 Pages) Holtek Semiconductor Inc – Touch I/O Flash MCU

BS83A02A-4/BS83A04A-3/BS83A04A-4
Touch I/O Flash MCU
Instruction
Table Location Bits
b9
b8
b7
b6
b5
b4
b3
b2
b1
b0
TABRD [m] PC9 PC8 @7 @6 @5 @4 @3 @2 @1 @0
TABRDL [m]
1
1
@7 @6 @5 @4 @3 @2 @1 @0
Table Location
Note: PC9, PC8: Current Program Counter bits
@7~@0: Table Pointer TBLP bits
b9~b0: Table address location bits
Table Program Example
The accompanying example shows how the table pointer and table data is defined and retrieved from
the devices. This example uses raw table data located in the last page which is stored there using the
ORG statement. The value at this ORG statement is "300H" which refers to the start address of the
last page within the 1K Program Memory of the microcontroller.
The table pointer is setup here to have an initial value of "06H". This will ensure that the first data
read from the data table will be at the Program Memory address "306H" or 6 locations after the start
of the last page. Note that the value for the table pointer is referenced to the first address of the last
page if the "TABRDL [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 "TABRDL
[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 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. 1.71
16
April 11, 2017