HD4046212RFS datasheet(18/157 Pages) RENESAS

18 / 157 page

HD404629R Series

LCD Data Area ($050–$083): Used for storing 52-digit LCD data which is automatically output to LCD

segments as display data. Data 1 lights the corresponding LCD segment; data 0 extinguishes it. Refer to

the LCD description for details.

Data Area ($090–$3BF): 464 digits from $090 to $25F have three banks, which can be selected by setting

the bank register (V: $03F). Before accessing this area, set the bank register to the required value (figure

7). The area from $260 to $3BF is accessed without setting the bank register.

Bit

Initial value

Read/Write

Bit name

—

Not used

—

Not used

R/W

Bank area selection

Bank 0 is selected

Bank 1 is selected

Bank 2 is selected

Not Used

Note: After reset, the value in the bank register is 0, and therefore bank 0 is

selected. If V1 = 1 and V0 = 1, no bank is selected, and the operation is not

guaranteed.

Bank register (V: $03F)

Figure 7 Bank Register (V)

Stack Area ($3C0–$3FF): Used for saving the contents of the program counter (PC), status flag (ST), and

carry flag (CA) at subroutine call (CAL or CALL instruction) and for interrupts. This area can be used as a

16-level nesting subroutine stack in which one level requires four digits. The data to be saved and the save

conditions are shown in figure 6.

The program counter is restored by either the RTN or RTNI instruction, but the status and carry flags can

only be restored by the RTNI instruction. Any unused space in this area is used for data storage.

HD4046212RFS Datasheet(PDF) 18 Page - Renesas Technology Corp