M28W640 STMicroelectronics, M28W640 Datasheet - Page 48

• Manufacturer Part Number: M28W640
• Description: 64 Mbit 4Mb x16/ Boot Block 3V Supply Flash Memory
• Manufacturer: STMicroelectronics

M28W640CT, M28W640CB
Figure 21. Erase Flowchart and Pseudo Code
Note: If an error is found, the Status Register must be cleared before further Program/Erase operations.
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Address & D0h
Read Status
Write Block
b4, b5 = 1
Write 20h
Register
b7 = 1
b3 = 0
b5 = 0
b1 = 0
Start
End
YES
YES
NO
YES
YES
NO
NO
YES
NO
NO
Sequence Error (1)
Erase to Protected
Erase Error (1)
Block Error (1)
V PP Invalid
Command
Error (1)
if ( (status_register.b5==1) )
/* erase error */
erase_command ( blockToErase ) {
if ( (status_register.b4==1) && (status_register.b5==1) )
/* command sequence error */
if (status_register.b1==1) /*program to protect block error */
if (status_register.b3==1) /*VPP invalid error */
}
do {
error_handler ( ) ;
error_handler ( ) ;
error_handler ( ) ;
error_handler ( ) ;
writeToFlash (any_address, 0x20) ;
writeToFlash (blockToErase, 0xD0) ;
/* only A12-A20 are significannt */
/* Memory enters read status state after
the Erase Command */
} while (status_register.b7== 0) ;
status_register=readFlash (any_address) ;
/* E or G must be toggled*/
AI03541b