SM5964 Datasheet, PDF (11/28 Pages) SyncMOS Technologies,Inc – 8 - bit single chip microcontroller with 64KB flash & 1K byte RAM embedded

SyncMOS Technologies Inc.
July 2002
SM5964
The lock bit N function is different from the flash protect function. The flash erase function can erase all of the flash memory
except for the locked ISP service program space. If the flash not been protected, the content of ISP service program still
can be read. If the flash been protected, the overall content of flash program memory space including ISP service program
space can not be read.
3.3 Program the ISP Service Program
After Lock Bit N is set and ISP service program been programmed, the ISP service program memory will be protected
(locked) automatically. The lock bit N has its own program/erase timing. It is different from the flash memory program/erase
timing so the locked ISP service program can not be erased by flash erase function. If user need to erase the locked ISP
service program, he can do it by writer only. User can not change ISP service program when SM5964 was in system.
3.4 Initiate ISP Service Program
To initiate the ISP service program is to load the program counter (PC) with start address of ISP service program and exe-
cute it. There are two ways to do so:
(1) Blank reset. Hardware reset with first flash address blank ($0000=#FFH) will load the PC with start address of ISP ser-
vice program.
(2) Execute jump instruction can load the start address of the ISP service program to PC.
User can initiate general 8052 INT function to initiate the ISP service program. After ISP service program executed, user
need to reset the SM5964, either by hardware reset or by WDT, or jump to the address $0000 to re-start the firmware pro-
gram.
ISP Registers - ISPFAH, ISPFAL, ISPFD and ISPC
ISP Flash Address-High Register (ISPFAH, $F4)
bit-7
bit-0
Read:
Write:
FA15
FA14
FA13
FA12
FA11
FA10
FA9
FA8
Reset value:
0
0
0
0
0
0
0
0
FA15 ~ FA8: flash address-high for ISP function
ISP Flash Address-Low Register (ISPFAL, $F5)
bit-7
bit-0
Read:
Write:
FA7
FA6
FA5
FA4
FA3
FA2
FA1
FA0
Reset value:
0
0
0
0
0
0
0
0
FA7 ~ FA0: flash address-low for ISP function
The ISPFAH & ISPFAL provide the 16-bit flash memory address for ISP function. The flash memory address should not
include the ISP service program space address. If the flash memory address indicated by ISPFAH & ISPFAL registers
Specifications subject to change without notice,contact your sales representatives for the most recent information.
11/28
Ver 1.0
PID 5964 07/02