SM5953
8-Bit Micro-controller
15KB with ISP Flash
& 256B RAM embedded
12. In-System Programming (Internal ISP)
The SM5953 can generate flash control signal by internal hardware circuit. Users utilize flash control register, flash
address register and flash data register to perform the ISP function without removing the SM5953 from the system.
The SM5953 provides internal flash control signals which can do flash program/chip erase/page erase/protect
functions. User need to design and use any kind of interface which SM5953 can input data. User then utilize ISP
service program to perform the flash program/chip erase/page erase/protect functions.
12.1 ISP service program
The ISP service program is a user developed firmware program which resides in the ISP service program space.
After user developed the ISP service program, user then determine the size of the ISP service program. User need
to program the ISP service program in the SM5953 for the ISP purpose.
The ISP service programs were developed by user so that it should includes any features which relates to the flash
memory programming function as well as communication protocol between SM5953 and host device which output
data to the SM5953. For example, if user utilize UART interface to receive/transmit data between SM5953 and host
device, the ISP service program should include baud rate, checksum or parity check or any error-checking
mechanism to avoid data transmission error.
12.2 Lock Bit (N)
The Lock Bit N has two functions: one is for service program size configuration and the other is to lock the ISP
service program space from flash erase function.
The ISP service program space address range $3000 to $3F7F. It can be divided as blocks of N. (N=0 to 8). When
N=0 means no ISP function. The maximum ISP service program allowed is 3.875K byte when N=8.
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 has been protected, the content of ISP
service program still can be read. If the flash has been protected, the overall content of flash program memory
space including ISP service program space can not be read. As given in Table 12-1.
Table 12-1 ISP code area
ISP service program address
No ISP service program
384 bytes ($3E00h ~ $3F7Fh)
896K bytes ($3C00h ~ $3F7Fh)
1.375K bytes ($3A00h ~ $3F7Fh)
1.875K bytes ($3800h ~ $3F7Fh)
2.375K bytes ($3600h ~ $3F7Fh)
2.875K bytes ($3400h ~ $3F7Fh)
3.375K bytes ($3200h ~ $3F7Fh)
3.875K bytes ($3000h ~ $3F7Fh)
0
1
2
3
4
5
6
7
8
ISP service program configurable in N (N= 0 ~ 8)
Specifications subject to change without notice contact your sales representatives for the most recent information.
ISSFD-M074
Ver B
SM5953
12/27/2013
- 38 -
SYNCMOS [ SYNCMOS TECHNOLOGIES,INC ]
