TC1784
Program Memory Unit (PMU)
User´s Manual
5-17
V1.1, 2011-05
PMU, V1.47
5.6.2.3
Operational Overview
In general, the operations of Program Flash and Data Flash are controlled identically.
Therefore, in the following, the operational overview is mainly presented only for the
Program Flash. When necessary, additional explanations are made for the Data Flash.
Standard Read
In standard read mode (the normal operating mode) the Flash memory appears like an
on-chip ROM. The Flash array module offers an asynchronous read access of 256-bit
read data (Data Flash: 64-bit read data) with an access time of 26 ns (Data Flash:
50 ns). Depending on the clock frequency of the PMU it has to wait a defined number of
wait cycles (see
). Instruction read accesses are 64-bit accesses. Because the
read data width of Program Flash is 256 bit, always a full burst transfer of four 64-bit
double-words is executed. Data operand reads are 64-bit accesses out of PFLASH or
DFLASH. In case of data access in cached address space, two double-words are
transferred. In case of non-cached data accesses only the addressed DW is accessed
and directly transferred to the CPU.
Note: The Flash module delivers always 64-bit read data. The addressed data (word,
half-word, byte depending on data type) within the double-word read data is
selected by the CPU.
The Flash addresses are mapped into the total address space of the controller with
different base addresses (see
“Address Mapping” on Page 5-26
).
The physical address range of the 24 Kbyte configuration sector starts also with address
zero, and it is mapped to the same base address as the Program Flash, but read and
direct write accesses to the config-sector are not possible for the user.
To eliminate any possibility of read data corruption, the Flash module provides ECC with
SEC-DED (Single Error Correction, Double Error Detection) capability over a 64-bit
double-word. For verify operations, the normal read can be combined with a margin
check (more critical control of sense amps). Single and double-bit errors are indicated in
the Flash status register and, if enabled, reported to the CPU by means of error
interrupts; the double-bit error causes a hardware trap (if not disabled for margin
checks).
Operation Control with Command Sequences
All operations besides normal read operations are initiated and controlled by command
sequences written to the flash interface&command state machine. During normal read
operations, a first write cycle to the Flash address space is automatically interpreted as
a command cycle, initiating a command sequence. The different write cycles of
command sequences are not only used for operation definitions such as program
commands or sector erase commands, but also as fail-safe and unlock cycles in order
Summary of Contents for TC1784
Page 1: ...User s Manual V1 1 2011 05 Microcontrollers TC1784 32 Bit Single Chip Microcontroller ...
Page 3: ...User s Manual V1 1 2011 05 Microcontrollers TC1784 32 Bit Single Chip Microcontroller ...
Page 950: ...TC1784 Direct Memory Access Controller DMA User s Manual 11 132 V1 1 2011 05 DMA V3 03 ...
Page 1949: ...TC1784 General Purpose Timer Array GPTA v5 User s Manual 21 297 V1 1 2011 05 GPTA v5 V1 14 ...
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