MIC3002_10 Datasheet, PDF (50/65 Pages) Micrel Semiconductor – FOM Management IC with Internal Calibration

Micrel, Inc.
MIC3002
OEM Password Entry (OEMPW)
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
D[2]
read/write
D[1]
read/write
D[0]
read/write
Default Value
0000 0000b = 00h (reset to zero at power-on)
Serial Address
A2h
Byte Address
If OEMCFG5-2 = 0: 120 – 123 = 78h - 7Bh (MSB is 7Bh
If OEMCFG5-2 = 1: 123– 126 = 7Bh – 7Eh (MSB is 7Eh)
This four-byte field is for entry of the password required to access the OEM area of the MIC3002’s memory and registers. A
valid OEM password will also permit access to the user areas of memory. The byte at address 123 (7Bh), 126 (7Eh) if
OMGFG5 bit2 =1, is the most significant byte. This field is compared to the four-byte OEMPWSET field at serial address A6h,
bytes 12 to 15. If the two fields match, access is allowed to the OEM areas of the MIC3002 non-volatile memory at serial
addresses A4h and A6h. The OEM password is set by writing the new value into OEMPWSET. The password comparison is
performed following the write to the MSB, address 7Bh (7Eh if OEMCFG5-2 = 1). This byte must be written last!
A four-byte burst-write sequence to address 78h(7Bh if OEMCFG5-2 = 1) may be used as this will result in the MSB being
written last. The new password will not take effect until after a power-on reset occurs or a warm reset is performed using the
RST bit in OEMCFG0. This allows the new password to be verified before it takes effect. This field is reset to all zeros at power
on. Any values written to these locations will be readable by the host regardless of the locked/unlocked status of the device. If
OEMPWSET is set to zero (00000000h), the MIC3002 will remain unlocked regardless of the contents of the OEMPW field.
This is the factory default security setting.
Byte
3
2
1
0
Weight
OEM Password Entry, Most Significant Byte (Address = 7Bh resp. 7Eh)
OEM Password Entry, 2nd Most Significant Byte (Address = 7Ah resp. 7Dh)
OEM Password Entry, 2nd Least Significant Byte (Address = 79h resp. 7Ch)
OEM Password Entry, Least Significant Byte (Address = 78h resp. 7Bh)
USER Password Setting (USRPWSET)
D[7]
read/write
D[6]
read/write
D[5]
read/write
D[4]
read/write
D[3]
read/write
D[2]
read/write
D[1]
read/write
D[0]
read/write
Default Value
0000 0000b = 00h
Serial Address
A2h
Byte Address
246 = F6h
This register is for setting the password required to access the USER area of the MIC3002’s memory and registers. This field is
compared to the USRPW field at serial address A2h, byte 247(F7h). If the two fields match, access is allowed to the USER
areas of the MIC3002 non-volatile memory at serial addresses A0h and A2h. If a valid USER password has not been entered,
writes to the serial ID fields, USRCTRL, and the user scratchpad areas of A0h and A2h will not be allowed, and USRPWSET
will be unreadable (returns all zeroes).
A USER password is set by writing the new value into USRPWSET. The new password will not take effect until after a power-
on reset occurs or a warm reset is performed using the RST bit in OEMCFG0. This allows the new password to be verified
before it takes effect. This register is non-volatile and will be maintained through power and reset cycles. A valid USER or OEM
password is required for access to this register. Otherwise, this register will read as 00h. Note: a valid OEM password overrides
the USER password setting. If a valid OEM password is currently in place, the user password will have no effect.
July 2007
50
M9999-073107-B
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