BS85B12-3 HOLTEK [Holtek Semiconductor Inc], BS85B12-3 Datasheet - Page 28

• Manufacturer Part Number: BS85B12-3
• Description: Touch Key Flash Type 8-Bit MCU with LCD/LED Driver
• Manufacturer: HOLTEK [Holtek Semiconductor Inc]

RAM Data Memory
Rev. 1.00
Structure
During the programming process the PA7 pin will be held low by the programmer disabling the normal
operation of the microcontroller and taking control of the PA0 and PA2 I/O pins for data and clock
programming purposes. The user must there take care to ensure that no other outputs are connected to
these two pins.
The 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, known as the Special Function Data
Memory. Here are located registers which are necessary for correct operation of the device. 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 Data Memory is known as the General Purpose Data Memory, which is reserved
for general purpose use. All locations within this area are read and write accessible under program
control.
The overall Data Memory is subdivided into two or three banks. The Special Purpose Data Memory
registers are accessible in all banks, with the exception of the EEC register at address 40H, which is
only accessible in Bank 1. Switching between the different Data Memory banks is achieved by setting
the Bank Pointer to the correct value. The start address of the Data Memory for all devices is the
address 00H.
Note:
BS85B12-3
BS85C20-3
Device
* may be resistor or capacitor. The resistance of * must be greater than 1k or the capacitance
of * must be less than 1nF.
Touch Key Flash MCU with LCD/LED Driver
Capacity
256 8
384 8
General Purpose Data Memory
80H~FFH
80H~FFH
Bank 0
22
BS85B12-3/BS85C20-3
80H~FFH
80H~FFH
Bank 1
80H~FFH
Bank 2
February 1, 2011