ht82k75rew Holtek Semiconductor Inc., ht82k75rew Datasheet - Page 13

• Manufacturer Part Number: ht82k75rew
• Description: Ht82m75rew/ht82k75rew 2.4ghz Transceiver 8-bit Otp Mcu
• Manufacturer: Holtek Semiconductor Inc.

Rev. 1.00
Only the destination of the lower-order byte in the ta-
ble is well-defined, the other bits of the table word are
transferred to the lower portion of TBLH, and the re-
maining 1-bit words are read as 0 . The Table
Higher-order byte register (TBLH) is read only. The ta-
ble pointer (TBLP, TBHP) is a read/write register (07H,
1FH), which indicates the table location. Before ac-
cessing the table, the location must be placed in the
TBLP and TBHP (If the configuration option TBHP is
disabled, the value in TBHP has no effect). The TBLH
is read only and cannot be restored. If the main rou-
tine and the ISR (Interrupt Service Routine) both em-
ploy the table read instruction, the contents of the
TBLH in the
main routine are likely to be changed by the table read
instruction used in the ISR. Errors can occur. In other
words, using the table read instruction in the main rou-
tine and the ISR simultaneously should be avoided.
However, if the table read instruction has to be applied
in both the main routine and the ISR, the interrupt
should be disabled prior to the table read instruction. It
The three methods are shown as follows: The in-
structions TABRDC [m] (the current page, one
page=256words), where the table location is de-
fined by TBLP (07H) in the current page. And the
configuration option TBHP is disabled (default).
The instructions TABRDC [m] , where the table lo-
cation is defined by registers TBLP (07H) and
TBHP (01FH). And the configuration option TBHP
is enabled.
The instructions TABRDL [m] , where the table lo-
cation is defined by register TBLP (07H) in the last
page (F00H~FFFH).
Table Read - TBLP only
13
Table Program Example
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
within the 4K Program Memory of device. The table
pointer is setup here to have an initial value of 06H .
This will ensure that the first data read from the data ta-
ble will be at the Program Memory address F06H 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 TABRDC [m] 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 TABRDL [m] in-
struction is executed.
F00H which refers to the start address of the last page
will not be enabled until the TBLH has been backed
up. All table related instructions require two cycles to
complete the operation. These areas may function as
normal program memory depending on the require-
ments.
Once TBHP is enabled, the instruction TABRDC [m]
reads the ROM data as defined by TBLP and TBHP
value. Otherwise, the configuration option TBHP is
disabled, the instruction TABRDC [m] reads the
ROM data as defined by TBLP and the current pro-
gram counter bits.
HT82M75REW/HT82K75REW
Table Read - TBLP/TBHP
June 11, 2010