PXD20RM Datasheet, PDF (820/1628 Pages) Freescale Semiconductor, Inc – PXD20 Microcontroller

Table 21-3. MCR Field Descriptions
Field
Description
SIZE Array Space Size. The value of the SIZE field depends on the size of the flash module. For PXD20, this bit field is
0b101, indicating a 2.0 MB array size (with 1.5 MB in high-address space). SIZE is read only.
LAS Low Address Space. The value of the LAS field corresponds to the configuration of the Low Address Space. For
PXD20, this bit field is 0b100, indicating eight 16 KB blocks and two 64 KB blocks. LAS is read only.
MAS
Mid Address Space. The value of the MAS field corresponds to the configuration of the Mid Address Space. The
value of the MAS field depends on the size of the flash module. For PXD20, this bit field is 0b0, indicating two 128
KB blocks. MAS is read only.
EER
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.
RWE
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.
SBC
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.
PEAS
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.
DONE
State Machine Status. Indicates if the flash module is performing a high-voltage operation. DONE is set to a 1 on
termination of the flash module reset, at the end of program and erase high-voltage sequences and after a
successful abort of a high voltage operation. DONE is cleared upon commencement of a high voltage operation or
on the resumption of a suspended operation.
0 Flash is executing a high-voltage operation
1 Flash is not executing a high-voltage operation
21-8
PXD20 Microcontroller Reference Manual, Rev. 1
Preliminary—Subject to Change Without Notice
Freescale Semiconductor