Datasheet M29W040B (STMicroelectronics) - 5

M29W040B COMMAND INTERFACE
If the address falls in a protected block then the All Bus Write operations to the memory are inter- Program command is ignored, the data remains preted by the Command Interface. Commands unchanged. The Status Register is never read and consist of one or more sequential Bus Write oper- no error condition is given. ations. Failure to observe a valid sequence of Bus During the program operation the memory will ig- Write operations will result in the memory return- nore all commands. It is not possible to issue any ing to Read mode. The long command sequences command to abort or pause the operation. Typical are imposed to maximize data security. program times are given in Table 6. Bus Read op- The commands are summarized in Table 5, Com- erations during the program operation will output mands. Refer to Table 5 in conjunction with the the Status Register on the Data Inputs/Outputs. text descriptions below. See the section on the Status Register for more details.
Read/Reset Command.
The Read/Reset com- mand returns the memory to its Read mode where After the program operation has completed the it behaves like a ROM or EPROM. It also resets memory will return to the Read mode, unless an the errors in the Status Register. Either one or error has occurred. When an error occurs the three Bus Write operations can be used to issue memory will continue to output the Status Regis- the Read/Reset command. ter. A Read/Reset command must be issued to re- set the error condition and return to Read mode. If the Read/Reset command is issued during a Block Erase operation or following a Programming Note that the Program command cannot change a or Erase error then the memory will take upto 10µs bit set at ‘0’ back to ‘1’. One of the Erase Com- to abort. During the abort period no valid data can mands must be used to set all the bits in a block or be read from the memory. Issuing a Read/Reset in the whole memory from ‘0’ to ‘1’. command during a Block Erase operation will
Unlock Bypass Command.
The Unlock Bypass leave invalid data in the memory. command is used in conjunction with the Unlock
Auto Select Command.
The Auto Select com- Bypass Program command to program the memo- mand is used to read the Manufacturer Code, the ry. When the access time to the device is long (as Device Code and the Block Protection Status. with some EPROM programmers) considerable Three consecutive Bus Write operations are re- time saving can be made by using these com- quired to issue the Auto Select command. Once mands. Three Bus Write operations are required the Auto Select command is issued the memory to issue the Unlock Bypass command. remains in Auto Select mode until another com- Once the Unlock Bypass command has been is- mand is issued. sued the memory will only accept the Unlock By- From the Auto Select mode the Manufacturer pass Program command and the Unlock Bypass Code can be read using a Bus Read operation Reset command. The memory can be read as if in with A0 = V Read mode. IL and A1 = VIL. The other address bits may be set to either VIL or VIH. The Manufacturer
Unlock Bypass Program Command.
The Un- Code for STMicroelectronics is 20h. lock Bypass Program command can be used to The Device Code can be read using a Bus Read program one address in memory at a time. The operation with A0 = V command requires two Bus Write operations, the IH and A1 = VIL. The other address bits may be set to either V final write operation latches the address and data IL or VIH. The Device Code for the M29W040B is E3h. in the internal state machine and starts the Pro- gram/Erase Controller. The Block Protection Status of each block can be read using a Bus Read operation with A0 = V The Program operation using the Unlock Bypass IL, A1 = V Program command behaves identically to the Pro- IH, and A16, A17 and A18 specifying the ad- dress of the block. The other address bits may be gram operation using the Program command. A set to either V protected block cannot be programmed; the oper- IL or VIH. If the addressed block is protected then 01h is output on the Data Inputs/ ation cannot be aborted and the Status Register is Outputs, otherwise 00h is output. read. Errors must be reset using the Read/Reset command, which leaves the device in Unlock By-
Program Command.
The Program command pass Mode. See the Program command for details can be used to program a value to one address in on the behavior. the memory array at a time. The command re- quires four Bus Write operations, the final write op-
Unlock Bypass Reset Command.
The Unlock eration latches the address and data in the internal Bypass Reset command can be used to return to state machine and starts the Program/Erase Con- Read/Reset mode from Unlock Bypass Mode. troller. Two Bus Write operations are required to issue the Unlock Bypass Reset command. 5/20 Document Outline Table 1. Signal Names Table 2. Absolute Maximum Ratings (1) Table 3. Uniform Block Addresses, M29W040B Table 4. Bus Operations Table 5. Commands Read/Reset. Auto Select. Program, Unlock Bypass Program, Chip Erase, Block Erase. Unlock Bypass. Unlock Bypass Reset. Erase Suspend. Erase Resume. Table 6. Program, Erase Times and Program, Erase Endurance Cycles (TA = 0 to 70˚C or –40 to 85˚C) Table 7. Status Register Bits Table 8. AC Measurement Conditions Table 9. Capacitance (TA = 25 ˚C, f = 1 MHz) Table 10. DC Characteristics (TA = 0 to 70˚C or –40 to 85˚C) Table 11. Read AC Characteristics (TA = 0 to 70˚C or –40 to 85˚C) Table 12. Write AC Characteristics, Write Enable Controlled (TA = 0 to 70˚C or –40 to 85˚C) Table 13. Write AC Characteristics, Chip Enable Controlled (TA = 0 to 70˚C or –40 to 85˚C) Table 14. Ordering Information Scheme Table 15. PLCC32 – 32 lead Plastic Leaded Chip Carrier, Package Mechanical Data Table 16. TSOP32 – 32 lead Plastic Thin Small Outline, 8 x 20mm, Package Mechanical Data Table 17. TSOP32 – 32 lead Plastic Thin Small Outline, 8 x 14mm, Package Mechanical Data Table 18. Revision History SUMMARY DESCRIPTION SIGNAL DESCRIPTIONS Address Inputs (A0-A18). Data Inputs/Outputs (DQ0-DQ7). Chip Enable (E). Output Enable (G). Write Enable (W). VCC Supply Voltage. VSS Ground. BUS OPERATIONS Bus Read. Bus Write. Output Disable. Standby. Automatic Standby. Special Bus Operations Electronic Signature. Block Protection and Blocks Unprotection. COMMAND INTERFACE Read/Reset Command. Auto Select Command. Program Command. Unlock Bypass Command. Unlock Bypass Program Command. Unlock Bypass Reset Command. Chip Erase Command. Block Erase Command. Erase Suspend Command. Erase Resume Command. STATUS REGISTER Data Polling Bit (DQ7). Toggle Bit (DQ6). Error Bit (DQ5). Erase Timer Bit (DQ3). Alternative Toggle Bit (DQ2). Figure 1. Logic Diagram Figure 2. PLCC Connections Figure 3. TSOP Connections Figure 4. Data Polling Flowchart Figure 5. Data Toggle Flowchart Figure 6. AC Testing Input Output Waveform Figure 7. AC Testing Load Circuit Figure 8. Read Mode AC Waveforms Figure 9. Write AC Waveforms, Write Enable Controlled Figure 10. Write AC Waveforms, Chip Enable Controlled Figure 11. PLCC32 – 32 lead Plastic Leaded Chip Carrier, Package Outline Figure 12. TSOP32 – 32 lead Plastic Thin Small Outline, 8 x 20mm, Package Outline Figure 13. TSOP32 – 32 lead Plastic Thin Small Outline, 8 x 14mm, Package Outline