HANGZHOU SILAN MICROELECTRONICS CO.,LTD

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2009.11.19

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FUNCTION DESCRIPTION

1.

Word width

Word width for SC73P2602 is 9-bit, that is 2K word is 2K×9-bit.

2.

Instruction period

Instruction and internal operation are both based on main clock. The instruction period is the time of executing a

whole instruction. There are single-/double-period instructions available for SC73P2602.

3.

PC

PC for SC73P2602 is 11-bit and the maximum addressable memory is 2K.

PC value is the address of next instruction to be executed and it is 0 after reset. In general, PC is added by 1

after executing an instruction because instructions for SC73P2602 is single-byte instruction. Fixed value is

evaluated to PC when executing jump, subprogram call and subprogram return.

4.

MBR

Memory buffer register (MBR) is the write-only, higher 5-bit of the program pointer. The ROM of SC73P1602 can

be divided into 15 blocks and each block has 128 bytes. These blocks can be addressed by the MBR. For

program jump, the BLOCK value containing the target address should be loaded to MBR before executing BSS

addr7 instruction.

5.

STACK

11-bit stack register is used for storing PC when calling subprogram. 3-level subprogram can be called for there is

only 3-level hardware stack registers in SC73P2602.

6.

B, H, D

4-bit data look-up pointer registers. Lower 3-bit of register B and all bits (4-bit) of H, D are used as pointers

pointing to data table when accessing constant data in OTP whose space of 2K can be used for data table or

program memory, otherwise, register B, H, D act as general purpose register as others. Constant data stored in

the table can be accessed through table look-up instruction.

7.

ALU

The arithmetic and logic unit plays a leading role in performing various operations of 4-bit binaries. The operation

of ALU will change the carry flag (CF) and the zero flag (ZF).

8.

ACC

4-bit accumulator, it is mostly used to store data and results.