Flash Program Memory; Structure; Special Vectors - Holtek HT45F23A Manual

Flash Program Memory

The Program Memory is the location where the user code or program is stored. For the devices
the Program Memory is Flash type, which means it can be programmed and re-programmed
a large number of times, allowing the user the convenience of code modification on the same
device. By using the appropriate programming tools, this Flash devices offer users the flexibility to
conveniently debug and develop their applications while also offering a means of field programming
and updating.

Structure

The Program Memory has a capacity of 2K×15~4K×16 . 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.

Special Vectors

Within the Program Memory, certain locations are reserved for special usage such as reset and
interrupts.
Location 000H
This vector is reserved for use by the devices 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 external interrupt 0. If the external interrupt pin receives an active edge,
the program will jump to this location and begin execution if the external interrupt is enabled and
the stack is not full.
Location 008H
This vector is used by the external interrupt 1. If the external interrupt pin receives an active edge,
the program will jump to this location and begin execution if the external interrupt is enabled and
the stack is not full.
Location 00CH
This internal vector is used by the Timer/Event Counter 0. If a Timer/Event Counter 0 overflow
occurs, the program will jump to this location and begin execution if the timer/event counter
interrupt is enabled and the stack is not full.
Location 010H
This internal vector is used by the Timer/Event Counter 1. If a Timer/Event Counter 1 overflow
occurs, the program will jump to this location and begin execution if the timer/event counter
interrupt is enabled and the stack is not full.
Location 014H
This internal vector is used by the SIM interrupt. When either an SPI or I
which one is selected, requires data transfer, the program will jump to this location and begin
execution if the SIM interrupt is enabled and the stack is not full.
Rev. 1.40
TinyPower Flash MCU with OPA & Comparators
TM
22
HT45F23A/HT45F24A
C bus, dependent upon
2
March 29, 2019