Electrical Characteristics
A.3
NVM
A.3.1
Timing Parameters
The time base for all NVM program or erase operations is derived from the bus clock using the FCLKDIV
register. The frequency of this derived clock must be set within the limits specified as f . The NVM
NVMOP
module does not have any means to monitor the frequency and will not prevent program or erase operation
at frequencies above or below the specified minimum. When attempting to program or erase the NVM
module at a lower frequency, a full program or erase transition is not assured.
The following sections provide equations which can be used to determine the time required to execute
specific flash commands. All timing parameters are a function of the bus clock frequency, f
. All
NVMBUS
program and erase times are also a function of the NVM operating frequency, f
timing parameters can be found in Table A-18.
. A summary of key
NVMOP
A.3.1.1
Erase Verify All Blocks (Blank Check) (FCMD=0x01)
The time required to perform a blank check on all blocks is dependent on the location of the first non-blank
word starting at relative address zero. It takes one bus cycle per phrase to verify plus a setup of the
command. Assuming that no non-blank location is found, then the time to erase verify all blocks is given
by:
1
--------------------
tcheck = 35500 ⋅
fNVMBUS
A.3.1.2
Erase Verify Block (Blank Check) (FCMD=0x02)
The time required to perform a blank check is dependent on the location of the first non-blank word starting
at relative address zero. It takes one bus cycle per phrase to verify plus a setup of the command.
Assuming that no non-blank location is found, then the time to erase verify a P-Flash block is given by:
1
--------------------
tpcheck = 33500 ⋅
fNVMBUS
Assuming that no non-blank location is found, then the time to erase verify a D-Flash block is given by:
1
--------------------
tdcheck = 2800 ⋅
fNVMBUS
S12P-Family Reference Manual, Rev. 1.13
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