CY8C3665PVI-008(2010) データシートの表示（PDF） - Cypress Semiconductor
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CY8C3665PVI-008 Datasheet PDF : 112 Pages
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PRELIMINARY
PSoC® 3: CY8C36 Family Datasheet
5. Memory
5.1 Static RAM
CY8C36 Static RAM (SRAM) is used for temporary data storage.
Up to 8 KB of SRAM is provided and can be accessed by the
8051 or the DMA controller. See Memory Map on page 19.
Simultaneous access of SRAM by the 8051 and the DMA
controller is possible if different 4-KB blocks are accessed.
5.2 Flash Program Memory
Flash memory in PSoC devices provides nonvolatile storage for
user firmware, user configuration data, bulk data storage, and
optional ECC data. The main flash memory area contains up to
64 KB of user program space.
Up to an additional 8 KB of flash space is available for ECC. If
ECC is not used this space can store device configuration data
and bulk user data. User code may not be run out of the ECC
flash memory section. ECC can correct one bit error and detect
two bit errors per 8 bytes of firmware memory; an interrupt can
be generated when an error is detected.
Flash is read in units of rows; each row is 9 bytes wide with 8
bytes of data and 1 byte of ECC data. When a row is read, the
data bytes are copied into an 8-byte instruction buffer. The CPU
fetches its instructions from this buffer, for improved CPU
performance.
Flash programming is performed through a special interface and
preempts code execution out of flash. The flash programming
interface performs flash erasing, programming and setting code
protection levels. Flash in-system serial programming (ISSP),
typically used for production programming, is possible through
both the SWD and JTAG interfaces. In-system programming,
typically used for bootloaders, is also possible using serial
interfaces such as I2C, USB, UART, and SPI, or any
communications protocol.
5.3 Flash Security
All PSoC devices include a flexible flash-protection model that
prevents access and visibility to on-chip flash memory. This
prevents duplication or reverse engineering of proprietary code.
Flash memory is organized in blocks, where each block contains
256 bytes of program or data and 32 bytes of ECC or
configuration data. A total of up to 256 blocks is provided on
64-KB flash devices.
The device offers the ability to assign one of four protection
levels to each row of flash. Table 5-1 lists the protection modes
available. Flash protection levels can only be changed by
performing a complete flash erase. The Full Protection and Field
Upgrade settings disable external access (through a debugging
tool such as PSoC Creator, for example). If your application
requires code update through a boot loader, then use the Field
Upgrade setting. Use the Unprotected setting only when no
security is needed in your application. The PSoC device also
offers an advanced security feature called Device Security which
permanently disables all test, programming, and debug ports,
protecting your application from external access (see Device
Security on page 56). For more information about how to take full
advantage of the security features in PSoC, see the PSoC 3
TRM.
Table 5-1. Flash Protection
Protection
Setting
Allowed
Not Allowed
Unprotected External read and write –
+ internal read and write
Factory
Upgrade
External write + internal External read
read and write
Field Upgrade Internal read and write External read and
write
Full Protection Internal read
External read and
write + internal write
Disclaimer
Note the following details of the flash code protection features on
Cypress devices.
Cypress products meet the specifications contained in their
particular Cypress datasheets. Cypress believes that its family of
products is one of the most secure families of its kind on the
market today, regardless of how they are used. There may be
methods, unknown to Cypress, that can breach the code
protection features. Any of these methods, to our knowledge,
would be dishonest and possibly illegal. Neither Cypress nor any
other semiconductor manufacturer can guarantee the security of
their code. Code protection does not mean that we are
guaranteeing the product as “unbreakable.”
Cypress is willing to work with the customer who is concerned
about the integrity of their code. Code protection is constantly
evolving. We at Cypress are committed to continuously
improving the code protection features of our products.
5.4 EEPROM
PSoC EEPROM memory is a byte-addressable nonvolatile
memory. The CY8C36 has up to 2 KB of EEPROM memory to
store user data. Reads from EEPROM are random access at the
byte level. Reads are done directly; writes are done by sending
write commands to an EEPROM programming interface. CPU
code execution can continue from flash during EEPROM writes.
EEPROM is erasable and writeable at the row level. The
EEPROM is divided into 128 rows of 16 bytes each.
The CPU can not execute out of EEPROM. There is no ECC
hardware associated with EEPROM. If ECC is required it must
be handled in firmware.
5.5 External Memory Interface
CY8C36 provides an external memory interface (EMIF) for
connecting to external memory devices. The connection allows
read and write accesses to external memories. The EMIF
operates in conjunction with UDBs, I/O ports, and other
hardware to generate external memory address and control
signals. At 33 MHz, each memory access cycle takes four bus
clock cycles.
Figure 5-1 is the EMIF block diagram. The EMIF supports
synchronous and asynchronous memories. The CY8C36
supports only one type of external memory device at a time.
External memory can be accessed through the 8051 xdata
space; up to 24 address bits can be used. See xdata Space on
page 21. The memory can be 8 or 16 bits wide.
Document Number: 001-53413 Rev. *I
Page 18 of 112
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