AT49LH004-33TC Atmel, AT49LH004-33TC Datasheet - Page 27

• Manufacturer Part Number: AT49LH004-33TC
• Description: IC FLASH 4MBIT 33MHZ 40TSOP
• Manufacturer: Atmel

Specifications of AT49LH004-33TC

• Format - Memory: FLASH
• Memory Type: FLASH
• Memory Size: 4M (512K x 8)
• Speed: 33MHz
• Interface: Parallel
• Voltage - Supply: 3 V ~ 3.6 V
• Operating Temperature: 0°C ~ 85°C
• Package / Case: 40-TSOP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

16.3
16.4
16.4.1
3383D–FLASH–6/05
Byte Program
Read Status Register
Clear Status Register
After issuing a sector erase command, the device’s Status Register may be checked to deter-
mine the status of the WSM and the erase operation. If the device detects a sector erase error,
the Status Register should be cleared before the system software attempts any corrective
actions. After a sector erase, the CUI remains in the Read Status Register mode until a new
command is issued.
Successful sector erase requires that the corresponding sector’s Write-Lock bit be cleared and
the corresponding hardware write protect pin (TBL or WP) be inactive. If using the Uniform
Sector Erase command to erase all of the sub-sectors, then all of the sub-sectors must have
their Write-Lock bits cleared and the TBL pin must be inactive. If a sector erase is attempted
when the sector is locked, the sector erase will fail, and the reason for the failure will be indi-
cated in the Status Register.
The erased state of the memory bits is a logical “1” (erased state of a byte is FFH).
The device is programmed on a byte-by-byte basis. The Byte Program command requires two
command cycles with the programming address and data being input on the second command
cycle. The device will automatically generate the required internal programming pulses, and all
programming operations are completely self-timed. Please note that the byte location being
programmed must have already been erased to FFH. A “0” cannot be programmed back to a
“1”; only an erase operation can convert “0”s to “1”s.
After the Byte Program command is written, the device’s Status Register may be checked to
determine the WSM status and the result of the program operation. If a program error is
detected, the Status Register should be cleared before any corrective action is taken by the
system software. After a byte program operation, the CUI remains in the Read Status Register
mode until a new command is issued.
A successful program operation also requires that the corresponding sector’s Write-Lock bit
be cleared, and the corresponding hardware write protect pin (TBL or WP) be inactive. If a pro-
gram operation is attempted when the sector is locked, the operation will fail, and the reason
for the failure will be indicated in the Status Register.
The Status Register (SR) may be read to determine when a sector erase or program operation
completes and whether the operation completed successfully. The Status Register may be
read at any time by writing the Read Status Register command. After writing the Read Status
Register command, all subsequent read operations will return data from the Status Register
until another valid command is written to the device.
Error flags (SR[5,4,1]) in the Status Register can only be set to “1”s by the WSM and can only
be reset by the Clear Status Register command. Therefore, if an error is detected, the Status
Register must be cleared before beginning another operation to avoid ambiguity.
AT49LH004
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