HT49R50 Holtek Semiconductor Inc, HT49R50 Datasheet - Page 12

• Manufacturer Part Number: HT49R50
• Description: 8-Bit Microcontroller
• Manufacturer: Holtek Semiconductor Inc

Of the two types of functional groups, the special
function registers consist of an Indirect address-
ing register 0 (00H), a Memory pointer register 0
(MP0;01H), an Indirect addressing register 1
(02H), a Memory pointer register 1 (MP1;03H), a
Bank pointer (BP;04H), an Accumulator
(ACC;05H), a Program counter lower-order byte
register (PCL;06H), a Table pointer (TBLP;07H),
RAM mapping
²
²
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a Table higher-order byte register (TBLH;08H), a
Real time clock control register (RTCC;09H), a
Status register (STATUS;0AH), an Interrupt
control register 0 (INTC0;0BH), a timer/event
counter 0 (TMR0;0DH), a timer/event counter 0
control register (TMR0C;0EH), a timer/event
counter 1 (TMR1;10H), a timer/event counter 1
control register (TMR1C;11H), I/O registers
(PA;12H, PB;14H, PC;16H), and Interrupt con-
trol register 1 (INTC1;1EH). On the other hand,
the general purpose data memory, addressed
from 60H to FFH, is used for data and control in-
formation under instruction commands.
The areas in the RAM can directly handle
arithmetic, logic, increment, decrement, and
rotate operations. Except some dedicated bits,
each bit in the RAM can be set and reset by
²SET [m].i² and ²CLR [m].i². They are also indi-
rectly accessible through the Memory pointer
register 0 (MP0;01H) or the Memory pointer
register 1 (MP1;03H).
Indirect addressing register
Location 00H and 02H are indirect addressing
registers that are not physically implemented.
Any read/write operation of [00H] and [02H] ac-
cesses the RAM pointed to by MP0 (01H) and
MP1(03H) respectively. Reading location 00H
or 02H indirectly returns the result 00H.
While, writing it indirectly leads to no opera-
tion.
The function of data movement between two indi-
rect addressing registers is not supported. The
memory pointer registers, MP0 and MP1, are
both 8-bit registers used to access the RAM by
combining corresponding indirect addressing reg-
isters. MP0 can only be applied to data memory,
while MP1 can be applied to data memory and
LCD display memory.
Accumulator - ACC
The accumulator (ACC) is related to the ALU
operations. It is also mapped to location 05H of
the RAM and is capable of operating with im-
mediate data. The data movement between two
data memory locations must pass through the
ACC.
August 18, 1999
HT49C50