The TC58FVT321/B321 can be programmed in either byte or word units. Auto-Program Mode is set using the
Program command. The program address is latched on the falling edge of the WE signal and data is latched on
the rising edge of the fourth Bus Write cycle (with WE control). Auto programming starts on the rising edge of
the WE signal in the fourth Bus Write cycle. The Program and Program Verify commands are automatically
executed by the chip. The device status during programming is indicated by the Hardware Sequence flag. To read
the Hardware Sequence flag, specify the address to which the Write is being performed
During Auto-Program execution, a command sequence for the bank on which execution is being performed
cannot be accepted. To terminate execution, use a hardware reset. Note that if the Auto-Program operation is
terminated in this manner, the data written so far is invalid.
Any attempt to program a protected block is ignored. In this case the device enters Read Mode 3 µs after the
rising edge of the WE signal in the fourth Bus Write cycle.
If an Auto-Program operation fails, the device remains in the programming state and does not automatically
return to Read Mode. The device status is indicated by the Hardware Sequence flag. Either a Reset command or
a hardware reset is required to return the device to Read Mode after a failure. If a programming operation fails,
the block which contains the address to which data could not be programmed should not be used.
The device allows 0s to be programmed into memory cells which contain a 1. 1s cannot be programmed into
cells which contain 0s. If this is attempted, execution of Auto Program will fail. This is a user error, not a device
error. A cell containing 0 must be erased in order to set it to 1.
Fast Program Mode
Fast Program is a function which enables execution of the command sequence for the Auto Program to be
completed in two cycles. In this mode the first two cycles of the command sequence, which normally requires four
cycles, are omitted. Writing is performed in the remaining two cycles. To execute Fast Program, input the Fast
Program command. Write in this mode uses the Fast Program command but operation is the same at that for
ordinary Auto-Program. The status of the device is indicated by the Hardware Sequence flag and read operations
can be performed as usual. To exit this mode, the Fast Program Reset command must be input. When the
command is input, the device will return to Read Mode.
The TC58FVT321/B321 features Acceleration Mode which allows write time to be reduced. Applying V
WP or ACC automatically sets the device to Acceleration Mode. In Acceleration Mode, Block Protect Mode
changes to Temporary Block Unprotect Mode. Write Mode changes to Fast Program Mode. Modes are switched by
signal; thus, there is no need for a Temporary Block Unprotect operation or to set or reset Fast
Program Mode. Operation of Write is the same as in Auto-Program Mode. Removing V
terminates Acceleration Mode.