PXS20RM Datasheet, PDF (565/1368 Pages) Freescale Semiconductor, Inc – PXS20 Microcontroller

Field
EER
RWE
SBC
PEAS
DONE
Flash Memory
Table 23-3. MCR Field Descriptions (continued)
Description
ECC Event Error. EER provides information on previous reads. If a double bit detection occurred,
the EER bit is set to a 1. This bit must then be cleared, or a reset must occur before this bit returns
to a 0 state. This bit may not be set by the user. In the event of a single bit detection and correction,
this bit is not be set. If EER is not set, or remains 0, this indicates that all previous reads (from the
last reset, or clearing of EER) are correct. Since this bit is an error flag, it must be cleared to a 0
by writing a 1 to the register location. A write of 0 has no effect.
0 Reads are occurring normally
1 An ECC Error occurred during a previous read
Read While Write Event Error. RWE provides information on previous RWW reads. If a Read While
Write error occurs, this bit is set to 1. This bit must then be cleared, or a reset must occur before
this bit returns to a 0 state. This bit may not be written to a 1 by the user. If RWE is not set, or
remains 0, this indicates that all previous RWW reads (from the last reset, or clearing of RWE) are
correct. Since this bit is an error flag, it must be cleared to a 0 by writing a 1 to the register location.
A write of 0 has no effect.
0 Reads are occurring normally
1 A Read While Write Error occurred during a previous read
Single Bit Correction. SBC provides information on previous reads provided the UT0[SPCE] is set.
If a single bit correction occurred, the SBC bit is set to a 1. This bit must then be cleared, or a
reset must occur before this bit returns to a 0 state. If SBC is not set, or remains 0, this indicates
that all previous reads (from the last reset, or clearing of SBC) did not require a correction. Since
this bit is an error flag, it must be cleared to a 0 by writing a 1 to the register location. A write of 0
has no effect.
0 Reads are occurring without corrections
1 A Single Bit Correction occurred during a previous read
Program/Erase Access Space. PEAS is used to indicate which space is valid for program and
erase operations, either main array space or shadow space. PEAS = 0 indicates that the main
address space is active for all FC program and erase operations. PEAS = 1 indicates the shadow
address space is active for program/erase. The value in PEAS is captured and held when the
shadow block is enabled with the first interlock write done for program or erase operations. The
value of PEAS is retained between sampling events (i.e. subsequent first interlock writes). The
value in PEAS may be changed during erase-suspended program, and reverts back to its’ original
state once the erase-suspended program is completed. PEAS is read only.
0 Shadow address space is disabled for program/erase and main address space enabled
1 Shadow address space is enabled for program/erase and main address space disabled
State Machine Status. DONE indicates if the flash module is performing a high voltage operation.
DONE is set to a 1 on termination of the flash module reset. DONE is read only. DONE is cleared
within Tdone (Appendix A) of a 0 to 1 transition of EHV which initiates a high voltage operation.
DONE is cleared within Tres (Appendix A) of resuming a suspended operation. DONE is set to a
1 at the end of program and erase high voltage sequences. DONE is set to a 1 within Tdones
(Appendix A) of a 1 to 0 transition of EHV which aborts a high voltage operation.
0 Flash is executing a high voltage operation
1 Flash is not executing a high voltage operation
Freescale Semiconductor
PXS20 Microcontroller Reference Manual, Rev. 1
23-15