TH58NS100DC Datasheet, PDF (41/43 Pages) Toshiba Semiconductor – TOSHIBA MOS DIGITAL INTEGRATED CIRCUIT SILICON GATE CMOS 1 - GBIT (128M X 8 BITS) CMOS NAND E2PROM ( 128M BYTE SmartMediaTM )

TH58NS100DC
(14) Invalid blocks (bad blocks)
The device contains unusable blocks. Therefore, the following issues must be recognized:
Bad Block
Referring to the Block status area in the redundant area allows the
system to detect bad blocks in the accordance with the physical data
format issued by the SSFDC Forum. Detect the bad blocks by checking the
Block Status Area at the system power-on, and do not access the bad
blocks in the following routine.
The number of valid blocks at the time of shipment is as follows:
Bad Block
Valid (Good) Block Number
MIN
8032
TYP.
¾
MAX
8192
UNIT
Block
Figure 26.
(15) Failure phenomena for Program and Erase operations
The device may fail during a Program or Erase operation.
The following possible failure modes should be considered when implementing a highly reliable system.
FAILURE MODE
DETECTION AND COUNTERMEASURE SEQUENCE
Block
Page
Single Bit
Erase Failure
Status Read after Erase ® Block Replacement
Programming Failure Status Read after Program ® Block Replacement
Programming Failure ^{(1) Block Verify after Program ® Retry}
1®0
(2) ECC
· ECC: Error Correction Code
· Block Replacement
Program
Error occurs
Buffer
memory
Block A
Block B
When an error happens in Block A, try to
reprogram the data into another (Block B) by
loading from an external buffer. Then, prevent
further system accesses to Block A (by creating
a bad block table or by using an another
appropriate scheme).
Figure 27.
Erase
When an error occurs for an Erase operation, prevent future accesses to this bad block (again by
creating a table within the system or by using another appropriate scheme).
(16) Chattering of Connector
There may be contact chattering when the device is inserted or removed from a connector.
This chattering may cause damage to the data in the device. Therefore, sufficient time must be allowed for
contact bouncing to subside when a system is designed with SmartMedia^TM.
(17) The device is formatted to comply with the Physical and Logical Data Format of the SSFDC Forum at the
time of shipping.
2001-03-21 41/43