HT48F70E datasheet(9/58 Pages) HOLTEK

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HT48F70E

Rev. 1.30

July 29, 2009

After setting up the table pointer, the table data can be

retrieved from the current Program Memory page or last

Program Memory page using the

²TABRDC[m]² or

²TABRDL [m]² instructions, respectively. When these in-

structions are executed, the lower order table byte from

the Program Memory will be transferred to the user de-

fined Data Memory register [m] as specified in the in-

struction. The higher order table data byte from the

Program Memory will be transferred to the TBLH special

byte will have uncertain values.

The following diagram illustrates the addressing/data

flow of the look-up table:

Table Program Example

The following example shows how the table pointer and

table data is defined and retrieved from the HT48F70E

device. This example uses raw table data located in the

last page which is stored there using the ORG state-

ment. The value at this ORG statement is

²1F00H²

which refers to the start address of the last page within

the 8K Program Memory of the microcontroller. The ta-

ble pointer is setup here to have an initial value of

²06H².

This will ensure that the first data read from the data ta-

ble will be at the Program Memory address

²1F06H² or 6

locations after the start of the last page. Note that the

value for the table pointer is referenced to the first ad-

dress of the present page if the

²TABRDC [m]² instruc-

tion 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

²TABRDL [m]² in-

struction is executed.

P r o g r a m

M e m o r y

P r o g r a m C o u n t e r

H i g h B y t e

T B L P

T B L H

S p e c i f i e d b y [ m ]

H i g h B y t e o f T a b l e C o n t e n t s

L o w B y t e o f T a b l e C o n t e n t s

Look-up Table

tempreg1

; temporary register #1

tempreg2

; temporary register #2

mov

a,06h

; initialise table pointer - note that this address

; is referenced

mov

tblp,a

; to the last page or present page

tabrdl

tempreg1

; transfers value in table referenced by table pointer

; to tempregl

; data at prog. memory address

²1F06H² transferred to

; tempreg1 and TBLH

dec

tblp

; reduce value of table pointer by one

tabrdl

tempreg2

; transfers value in table referenced by table pointer

; to tempreg2

; data at prog.memory address

²1F05H² transferred to

; tempreg2 and TBLH

; in this example the data

²1AH² is transferred to

; tempreg1 and data

²0FH² to register tempreg2

org

1F00h

; sets initial address of HT48F70E last page

00Ah, 00Bh, 00Ch, 00Dh, 00Eh, 00Fh, 01Ah, 01Bh

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