Samsung S3F401F - Manual (Page 70)

INTERNAL FLASH ROM S3F401F_UM_REV1.00
5-10
5.2 JTAG INTERFACE PROTECTION BIT 8
This Bit is used for JTAG Access enable or disable (If chip designers would like to debug through JTAG in initial chip
development state, JTAG Interface Protection Bit should be disabled, but, In final design development state, If chip
designers enable the JTAG interface Protection, other user can not access the flash memory data via JTAG
interface)
5.3 HARDWARE PROTECTION BIT 17
If Hardware Protection was enabled, user cannot write or erase the data in a flash memory area. In addition
Protection Option and Smart Option cannot be set or released. Hardware Protection function affects a tool program
mode as well as a user program mode. This protection can be released only by the chip erase execution.
Hardware Protection can be set in user program mode as follows. You should write 0x0E3C into the address and the
proper data (Refer to the above Protection Bit table) into the data register (FMDATA), respectively. As a next step,
you should write the values (0x5A5A5A5A) into key register(FMKEY). Finally, set FMUCON. Please refer to
figure3(Option Program Flowchart).
For enable to Hardware Protection, two Option registers, Protection Option(FMADDR: 0x0E3C) and Smart
Option(FMADDR: 0x0E38) are used. That is, Protection Option is used for enabling the hardware protection of the
selected group of sectors by Smart Option. Smart Option is used for selecting the group of sectors for hardware
protection. When you set the Smart Option, hardware protection bit in Protection Option must be disabled. After you
set the Smart Option, you should enable the hardware protection bit in Protection Option(FMADDR: 0x0E3C) On the
other way, you can set Hardware Protection in tool program mode by executing its functions and release Hardware
Protection by chip erase, which results in initializing all Protection bits, smart option bits and erasing internal Flash
ROM data,
5.3.1 SMART OPTION FMADDR - 0X0E38
In the Hardware protection function, the protection on certain block can be disabled by setting the corresponding
smart option bits. Four bits are allocated in the address of smart option (0x0E38) for this function.
To enable the protection function on a certain block,
> Configure the smart option bits in advance
> Configure the Hardware Protection Option (0x0E3C).
Table 5-3. Smart Option Address Configuration
FMADDR FMDATA Description Reset Value
H/W protection is disable / enable : These bits are each mapped
to a corresponding group which is composed of 32 sectors(32KB). In
other word, the Bit[0] is mapped from sector 1 to sector 16. And the
Bit[1] is mapped from sector 17 to sector 32 and so on.
Therefore, these 16 bits are used for 256KB internal Flash.
0 = Enable H/W protection of selected group
0x00000E38 Bit [15:0]
1 = Disable H/W protection of selected group
0xFFFF