SC73P1601

HANGZHOU SILAN MICROELECTRONICS CO.,LTD

REV:1.4

2009.08.03

Http: www.silan.com.cn

Page 6 of 22

2. MBR

Memory buffer register (MBR) is write-only, higher 4-bit of the program pointer. The EPROM of SC73P1601

can be divided into 8 blocks. Each block is 128 bytes. The 8 blocks can be addressed by the MBR. When the

program starts executing a branch instruction, it must load the corresponding value to the MBR register, and then

executes the command BSS label.

3. STACK

Stack register stores the previous value of program pointer during execution of subroutine calls, 11 bits. There

is two-level hardware stack register, so two-level programs can be called. When the user tries to make more than

two-level program call, an error will occur.

4. B, H, D

Referred to as the pointer to data table. BHD are separately 2 bits, 4 bits and 4 bits. The 1K EPROM space of

SC73P1601 can be used as the data table which can be diplex with program space. When addressing the fixed

data of EPROM, the registers act as the pointers to the data table (to form the EPROM address according to

BHD order). In other cases, the H, D registers can be used as general purpose registers. Fixed data stored in the

data table can be addressed by the transmit instructions. When executing the transmit-instructions, the program

will look for the data from the correspond space of EPROM. The low 10 bits address of the EPROM are

composed of two lower bits of B , four bits of H and four bits of D.

When the most significant bit is 1, P53 transmits the data with carrier; while the most significant bit is 0, P53

transmits the data without carrier. The second bit of B is of no real use, and it is set 0 by the software at program

imitation.

5. PROM

Address

1k x 9bits

000H

001H

002H

01FH

Subroutine call start address

020H

3FFH

Normal program Area

(can be duplex as data table)

6. CH0、CH1、CL0、CL1

CH0, CH1, CL0, CL1 are carrier high and low level control registers, which can control the high-low level of

carrier is (CH＋1)/fosc and(CL＋1)/fosc.