TMS29F040

524288 BY 8BIT

FLASH MEMORY

SMJS820C − APRIL 1996 − REVISED JUNE 1998

6

POST OFFICE BOX 1443

algorithm selection mode

The algorithm-selection mode provides access to a binary code that matches the device with its proper

on address pin A9. Address pins A1 and A6 must be logic-low. Two bytes of code are accessed by toggling

available to be placed on address pin A9. Table 2 shows the binary algorithm-selection codes for the

TMS29F040.

ALGORITHM SELECTION

A0

DQ7

DQ6

DQ5

DQ4

DQ3

DQ2

DQ1

DQ0

HEX

Byte 0

0

0

0

0

0

0

0

0

1

01h

Byte 1

1

1

0

1

0

0

1

0

0

A4h

† A1 = VIL, A6 = VIL, E = G = VIL

erasure and programming

Erasure and programming of the TMS29F040 are accomplished by writing a sequence of commands using

standard microprocessor-write timings. The commands are written to a command register and input to the

command-state machine (CSM). The CSM interprets the command entered and initiates program, erase,

suspend, and resume operations as instructed. The CSM acts as the interface between the write-state machine

(WSM) and the external chip operations. The WSM controls all voltage generation, pulse generation,

preconditioning, and verification of the memory contents. Program and sector/chip-erase functions are fully

automatic. Once the end of a program or erase operation is reached, the device internally resets to the read

device resets to the read mode. If a byte-program or chip-erase operation is in progress, additional

program / erase commands are ignored until the operation in progress completes.

command definitions

Device operating modes are selected by writing specific address and data sequences into the command

register. Table 3 defines the valid command sequences. Writing incorrect address and data values or writing

them in the incorrect sequence causes the device to reset to the read mode. The command register does not

occupy an addressable memory location. The register stores the command sequence along with the address

for a more complete description.