ht827a0 Holtek Semiconductor Inc., ht827a0 Datasheet - Page 11

• Manufacturer Part Number: ht827a0
• Description: 8-bit Microcontroller With Voice Rom
• Manufacturer: Holtek Semiconductor Inc.

RAM mapping
11
control registers (PAC; 13H, PBC; 15H, PCC;
17H, PDC; 19H, PEC; 1BH). The 20H to 2FH
are used for sound and tone (melody) synthesis.
The function registers include a lower-order
byte register (DAL; 20H) of D/A data,
higher-order byte register (DAH;21H) of D/A
data , volume control register (VCR; 22H), sam-
pling rate control register (SRC; 23H), beat con-
trol register (BEAT; 28H), tempo control
register (TEMPO; 29H), tone control register
(TONE; 2AH) and voice ROM control register
(ROMC; 2CH). The remaining space before 30H
is reserved for future expansion. Reading these
remaining locations will get ²00H². The general
purpose data memory is used for data and con-
trol information under instruction commands.
All of the areas of data memory can handle
arithmetic, logic, increment, decrement and ro-
tate operations directly. Except for some dedi-
cated bits, each bit in the data memory can be
set and reset by ²SET [m].i² and ²CLR [m].i²,
and can also be indirectly accessed through a
memory pointer register (MP; 01H).
Indirect addressing register
Location 00H is an indirect addressing register
that is not physically implemented. Any
read/write operation of [00H] accesses the data
memory pointed to by MP (01H). Indirectly read-
ing location 00H will return the result to 00H
whereas, indirectly writing it will have no effect.
Arithmetic and logic unit - ALU
This circuit performs 8-bit arithmetic and logic
operations. ALU provides the following func-
tions:
·
·
·
·
·
ALU not only saves the results of a data opera-
tion but also change the status register.
Arithmetic operations (ADD, ADC, SUB,
SBC, DAA)
Logic operations (AND, OR, XOR, CPL)
Rotation (RL, RR, RLC, RRC)
Increment & decrement (INC, DEC)
Branch decision (SZ, SNZ, SIZ, SDZ ....)
March 15, 2000
HT827A0