HT82A520R Datasheet, PDF (11/72 Pages) Holtek Semiconductor Inc – Full Speed USB 8-Bit OTP MCU with SPI

The following example shows how the table pointer and
table data is defined and retrieved from the
microcontroller. This example uses raw table data lo-
cated in the last page which is stored there using the
ORG statement. The value at this ORG statement is
²F00H² which refers to the start address of the last page
within the 4K Program Memory of device. The table
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 ²F06H² 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.
HT82A520R/HT82A620R
P ro g ra m C o u n te r
H ig h B y te
TB LP
P ro g ra m
M e m o ry
TB LH
T a b le C o n te n ts H ig h B y te
S p e c ifie d b y [m ]
T a b le C o n te n ts L o w B y te
T a b le R e a d - T B L P O n ly
TBH P
TB LP
P ro g ra m
M e m o ry
TB LH
S p e c ifie d b y [m ]
H ig h B y te o f T a b le C o n te n ts L o w B y te o f T a b le C o n te n ts
T a b le R e a d - T B L P / T B H P
tempreg1 db
tempreg2 db
:
:
? ; temporary register #1
? ; 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 ²F06H² 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 ²F05H² transferred to
; tempreg2 and TBLH
; in this example the data ²1AH² is transferred to
; tempreg1 and data ²0FH² to register tempreg2
; the value ²00H² will be transferred to the high byte
; register TBLH
org F00h
; sets initial address of last page
dc 00Ah, 00Bh, 00Ch, 00Dh, 00Eh, 00Fh, 01Ah, 01Bh
:
:
Table Location Bits
Instruction
b11 b10 b9 b8 b7 b6 b5 b4 b3 b2 b1 b0
TABRDC [m] PC11 PC10 PC9 PC8 @7 @6 @5 @4 @3 @2 @1 @0
TABRDL [m] 1
1
1
1
@7 @6 @5 @4 @3 @2 @1 @0
Table Location
Note: PC11~PC8: Current Program Counter bits
@7~@0: Table Pointer TBLP bits
TBHP register bit3~bit0 when TBHP is enabled
Rev.1.00
11
October 23, 2009