HT83F10 HOLTEK [Holtek Semiconductor Inc], HT83F10 Datasheet - Page 12

• Manufacturer Part Number: HT83F10
• Description: Flash Type Voice OTP MCU
• Manufacturer: HOLTEK [Holtek Semiconductor Inc]

Special Function Registers
To ensure successful operation of the microcontroller,
certain internal registers are implemented in the RAM
Data Memory area. These registers ensure correct op-
eration of internal functions such as timers, interrupts,
watchdog, etc., as well as external functions such as I/O
data control. The location of these registers within the
RAM Data Memory begins at the address 00H . Any
unused Data Memory locations between these special
function registers and the point where the General Pur-
pose Memory begins is reserved for future expansion
purposes, attempting to read data from these locations
will return a value of 00H .
Rev. 1.00
Special Purpose Data Memory Structure
12
Indirect Addressing Register - IAR
The Indirect Addressing Register, IAR, although having
location in normal RAM register space, do not actually
physically exist as normal registers.
The method of indirect addressing for RAM data manip-
ulation uses the Indirect Addressing Register and Mem-
ory Pointer, in contrast to direct memory addressing,
where the actual memory address is specified.
Actions on the IAR register will result in no actual read or
write operation to these register but rather to the mem-
ory location specified by their corresponding Memory
Pointer, MP. Acting as a pair, IAR and MP can together
only access data. As the Indirect Addressing Registers
are not physically implemented, reading the Indirect Ad-
dressing Register indirectly will return a result of 00H
and writing to the registers indirectly will result in no op-
eration.
Memory Pointer - MP
For all devices, Memory Pointer, known as MP is pro-
vided. These Memory Pointers are physically imple-
mented in the Data Memory and can be manipulated in
the same way as normal register providing a convenient
way with which to address and track data. When any op-
eration to the relevant Indirect Addressing Registers is
carried out, the actual address that the microcontroller is
directed to, is the address specified by the related Mem-
ory Pointer. MP, together with Indirect Addressing Reg-
ister, IAR, are used to access data. Note that bit 7 of the
Memory Pointers is not required to address the full
memory space and will return a value of 1 if read.
HT83FXX
May 12, 2009