HT37B90 datasheet(14/80 Pages) HOLTEK

14 / 80 page

HT37B90/HT37B70/HT37B50/HT37B30

Rev.1.00

June22,2017

ROMBankPointer(2DH)

The program memory is organized into 64/32/16/8 banks for HT37B90/70/50/30 and each bank into 8K

´16 bits of pro-

gram ROM. BP1.7~BP1.0 is used as the bank pointer. After an instruction has been executed to write data to the BP1

register to select a different bank, note that the new bank will not be selected immediately. It is until the instruction

²JMP² or ²CALL² orinterrupthascompletedexecutionthatthebankwillbeactuallyselected.

BitNo.

Function

BP1(2DH)

0~7

00000000b=SelectROMBank0(0000h~1FFFh)

00000001b=SelectROMBank1(2000h~3FFFh)

00000010b=SelectROMBank2(4000h~5FFFh)

00000011b=SelectROMBank3(6000h~7FFFh)

00011110b=SelectROMBank30(3C000h~3DFFFh)

00011111b=SelectROMBank31(3E000h~3FFFFh)

00111110b=SelectROMBank62(7C000h~7DFFFh)

00111111b=SelectROMBank63(7E000h~7FFFFh)

Note:

FortheHT37B90,theROMbankpointregisteris6bitswideeffectively, i.e.fromb5~b0.

FortheHT37B70,theROMbankpointregisteris5bitswideeffectively, i.e.fromb4~b0.

FortheHT37B50,theROMbankpointregisteris4bitswideeffectively, i.e.fromb3~b0.

FortheHT37B30,theROMbankpointregisteris3bitswideeffectively, i.e.from b2~b0.

RAMDataMemory

The RAM Data Memory is a volatile area of 8-bit wide

RAM internal memory and is the location where

temporary information is stored. Divided into two

sections, the first of these is an area of RAM where

special function registers are located. These registers

have fixed locations and are necessary for correct

operationofthedevice.

Many of these registers can be read from and written to

directly under program control, however, some remain

protected from user manipulation. The second area of

RAM Data Memory is reserved for general purpose use.

All locations within this area are read and write accessi-

bleunderprogramcontrol.

Structure

The RAM Data Memory is subdivided into 4 or 8 banks,

known as Bank 0 to Bank 3 or Bank 7, all of which are

implemented in 8-bit wide RAM. Most of the RAM Data

Memory is located in Bank 0 which is also subdivided

into two sections, the Special Purpose Data Memory

and the General Purpose Data Memory. The start ad-

dress of the Data Memory is the address

²00H². Regis-

ters which are common to all microcontrollers, such as

ACC, PCL, etc., have the same Data Memory address.

Bank 1 of the RAM Data Memory is located at address

²60H².

The RAM data memory is designed with 640

´8 bits or

1280

´8 bits with 4 or 8 RAM banks. There are two RAM

BANKpointers(RBP1andRBP2)controlBank0~7.

The data memory is designed with 256 bytes and di-

vided into five functional groups: special function regis-

ters (00H~1FH), music synthesis controller registers

(20H~2FH), ADPCM decoder controller register

(30H~35H), the other function (35H~5FH) and general

purposedatamemory(60H~FFH).

They are also indirectly accessible through Memory

S p e c i a l P u r p o s e

D a t a M e m o r y

0 0 H

5 F H

6 0 H

0 F F H

B a n k 0

B a n k 3

G e n e r a l P u r p o s e

D a t a M e m o r y

( 1 6 0 B y t e s )

G e n e r a l P u r p o s e

D a t a M e m o r y

( 1 6 0 B y t e s )

Bank0~Bank3RAMDataMemoryStructure-

HT37B70/50/30

S p e c i a l P u r p o s e

D a t a M e m o r y

0 0 H

5 F H

6 0 H

0 F F H

B a n k 0

B a n k 7

G e n e r a l P u r p o s e

D a t a M e m o r y

( 1 6 0 B y t e s )

G e n e r a l P u r p o s e

D a t a M e m o r y

( 1 6 0 B y t e s )

Bank0~Bank7RAMDataMemoryStructure-

HT37B90

HT37B90 Datasheet(PDF) 14 Page - Holtek Semiconductor Inc

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