HT46R34 datasheet(7/43 Pages) HOLTEK

7 / 43 page

HT46R32/HT46R34

Rev. 1.10

March 16, 2007

Program Memory

- ROM

The program memory is used to store the program in-

structions which are to be executed as well as table data

and interrupt entries. It is structured into 2K

´14 bits for

the HT46R32 device and 4K x 15 bits for the HT46R34

device, which can be addressed by both the program

counter and table pointer.

Certain locations in the program memory are reserved

for use by the reset and by the interrupt vectors.

· Location 000H

This vector is reserved 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 INT.Ifthe

external interrupt pin on the device receives a low go-

ing edge, the program will jump to this location and be-

gin execution if the external interrupt is enabled and

the stack is not full.

· Location 008H

This vector is used by the Timer/Event Counter. If a

timer overflow occurs, the program will jump to this loca-

tion and begin execution if the timer interrupt is enabled

and the stack is not full.

· Location 00CH

This vector is used by the A/D converter. When an A/D

cycle conversion is complete, the program will jump to

this location and begin execution if the A/D interrupt is

enabled and the stack is not full.

· Table location

Any location in the Program Memory space can be

used as a look-up table. The instructions

²TABRDC

[m]

² (the current page, 1 page=256 words) and

²TABRDL [m]² (the last page) transfer the contents of

the lower-order byte to the specified data memory,

and the higher-order byte to TBLH. Only the destina-

tion of the lower-order byte in the table is well-defined,

the other bits of the table word are transferred to the

lower portion of TBLH, and the remaining bits are read

²0². The Table Higher-order byte register (TBLH) is

read only. The table pointer (TBLP) is a read/write reg-

ister, which indicates the table location. Before ac-

cessing the table, the location must be placed in

TBLP. The TBLH register is read only and cannot be

restored. If the main routine and the ISR, Interrupt

Service Routine, both employ the table read instruc-

tion, the contents of the TBLH in the main routine are

likely to be changed by the table read instruction used

Instruction

Table Location

*11

*10

TABRDC [m]

P11

P10

TABRDL [m]

1111

Table Location

Note:

*11~*0: Table location bits

P11~P8: Current program counter bits

@7~@0: Table pointer bits

For the HT46R32 device the Table address is 11 bits wide, i.e. from b10~b0, therefore the b11 column in the

table is not applicable.

P r o g r a m

M e m o r y

D e v i c e I n i t i a l i z a t i o n P r o g r a m

E x t e r n a l I n t e r r u p t S u b r o u t i n e

T i m e r / E v e n t C o u n t e r I n t e r r u p t S u b r o u t i n e

L o o k - u p T a b l e ( 2 5 6 w o r d s )

N o t e : n r a n g e s f r o m 0 t o 7

A / D C o n v e r t e r I n t e r r u p t S u b r o u t i n e

n F F H

7 F F H

7 0 0 H

1 4 b i t s

0 0 0 H

0 0 4 H

0 0 8 H

0 0 C H

n 0 0 H

Program Memory

- HT46R32

P r o g r a m

M e m o r y

D e v i c e I n i t i a l i z a t i o n P r o g r a m

E x t e r n a l I n t e r r u p t S u b r o u t i n e

T i m e r / E v e n t C o u n t e r I n t e r r u p t S u b r o u t i n e

L o o k - u p T a b l e ( 2 5 6 w o r d s )

N o t e : n r a n g e s f r o m 0 t o F

A / D C o n v e r t e r I n t e r r u p t S u b r o u t i n e

n F F H

F F F H

F 0 0 H

1 5 b i t s

0 0 0 H

0 0 4 H

0 0 8 H

0 0 C H

n 0 0 H

Program Memory

- HT46R34

HT46R34 Datasheet(PDF) 7 Page - Holtek Semiconductor Inc

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