HT66F20 datasheet(27/250 Pages) HOLTEK

27 / 250 page

HT66F20/HT66F30/HT66F40/HT66F50/HT66F60

HT66FU30/HT66FU40/HT66FU50/HT66FU60

Rev. 1.20

June 4, 2010

Bank Pointer

- BP

Depending upon which device is used, the Program and

Data Memory are divided into several banks. Selecting

the required Program and Data Memory area is

achieved using the Bank Pointer. Bit 5 of the Bank

Pointer is used to select Program Memory Bank 0 or 1,

while bits 0~2 are used to select Data Memory Banks

0~4.

The Data Memory is initialised to Bank 0 after a reset,

except for a WDT time-out reset in the Power Down

Mode, in which case, the Data Memory bank remains

unaffected. It should be noted that the Special Function

Data Memory is not affected by the bank selection,

which means that the Special Function Registers can be

accessed from within any bank. Directly addressing the

Data Memory will always result in Bank 0 being ac-

cessed irrespective of the value of the Bank Pointer. Ac-

cessing data from banks other than Bank 0 must be

implemented using Indirect addressing.

As both the Program Memory and Data Memory share

the same Bank Pointer Register, care must be taken

during programming.

Device

Bit

76543210

HT66F20

HT66F40

¾¾¾¾¾¾¾

DMBP0

HT66F30

HT66F50

¾¾¾¾¾¾

DMBP1

DMBP0

HT66F60

¾¾

PMBP0

¾¾

DMBP2

DMBP1

DMBP0

BP Registers List

· BP Register

¨ HT66F20/HT66F40

Bit

76543210

Name

¾¾¾¾¾¾¾

DMBP0

R/W

¾¾¾¾¾¾¾

R/W

POR

¾¾¾¾¾¾¾

Bit7~1

Unimplemented, read as

²0²

Bit 0

DMBP0: Select Data Memory Banks

0: Bank 0

1: Bank 1

¨ HT66F30/HT66F50

Bit

76543210

Name

¾¾¾¾¾¾

DMBP1

DMBP0

R/W

¾¾¾¾¾¾

R/W

POR

¾¾¾¾¾¾

Bit7~2

Unimplemented, read as

²0²

Bit1~0

DMBP1, DMBP0: Select Data Memory Banks

00: Bank 0

01: Bank 1

10: Bank 2

11: Undefined

HT66F20 Datasheet(PDF) 27 Page - Holtek Semiconductor Inc

HT66F20 Datasheet(HTML) 27 Page - Holtek Semiconductor Inc

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