ht82a836r Holtek Semiconductor Inc., ht82a836r Datasheet - Page 9

• Manufacturer Part Number: ht82a836r
• Description: Usb Audio Mcu
• Manufacturer: Holtek Semiconductor Inc.

Arithmetic and Logic Unit - ALU
The arithmetic-logic unit or ALU is a critical area of the
microcontroller that carries out arithmetic and logic op-
erations of the instruction set. Connected to the main
microcontroller data bus, the ALU receives related in-
struction codes and performs the required arithmetic or
logical operations after which the result will be placed in
the specified register. As these ALU calculation or oper-
ations may result in carry, borrow or other status
changes, the status register will be correspondingly up-
dated to reflect these changes. The ALU supports the
following functions:
Program Memory
The Program Memory is the location where the user
code or program is stored. The device contains
One-Time Programmable, OTP, memory where users
can program their application code into the device. By
using the appropriate programming tools, OTP devices
offer users the flexibility to freely develop their applica-
tions, which may be useful during debug or for products
requiring frequent upgrades or program changes. OTP
devices are also applicable for use in applications that
require low or medium volume production runs.
Organisation
The Program Memory has a capacity of 8K by 16 bits.
The Program Memory is addressed by the Program
Counter and also contains data, table information and
interrupt entries. Table data, which can be setup in any
location within the Program Memory, is addressed by
separate table pointer registers.
Rev. 1.00
Arithmetic operations: ADD, ADDM, ADC, ADCM,
SUB, SUBM, SBC, SBCM, DAA
Logic operations: AND, OR, XOR, ANDM, ORM,
XORM, CPL, CPLA
Rotation RRA, RR, RRCA, RRC, RLA, RL, RLCA,
RLC
Increment and Decrement INCA, INC, DECA, DEC
Branch decision, JMP, SZ, SZA, SNZ, SIZ, SDZ,
SIZA, SDZA, CALL, RET, RETI
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Special Vectors
Within the Program Memory, certain locations are re-
served for special usage such as reset and interrupts.
Location 000H
This vector is reserved for use by the device reset for
program initialisation. After a device reset is initiated, the
program will jump to this location and begin execution.
Location 004H
This vector is used by the USB interrupt. If a USB in-
terrupt occurs, the program will jump to this location
and begin execution if the USB interrupt is enabled
and the stack is not full.
Location 008H
This vector is used by the Timer/Event Counter 0. If a
counter overflow occurs, the program will jump to this
location and begin execution if the timer interrupt is
enabled and the stack is not full.
Location 00CH
This vector is used by the Timer/Event counter 1. If a
counter overflow occurs, the program will jump to this
location and begin execution if the timer interrupt is
enabled and the stack is not full.
Location 010H
This vector is used by the play interrupt service pro-
gram. If play data occurs, the program will jump to this
location and begin execution if the play interrupt is en-
abled and the stack is not full.
Location 014H
This vector is used by the Multi-function interrupt. If an
interrupt results from a serial interface interrupt, an
end of 12-bit A/D conversion cycle or an external inter-
rupt, the program will jump to this location and begin
execution if the relevant interrupt is enabled and the
stack is not full.
Location 018H
This area is used by the Record interrupt. If record
data occurs, the program will jump to this location and
begin execution if the timer interrupt is enabled and
the stack is not full.
Program Memory Structure
HT82A836R
March 20, 2008