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PSD4256G6V
This is preliminary information on a new product now in development or undergoing evaluation. Details are subject to change without notice.
SUMMARY DESCRIPTION
The PSD family of memory syst e ms for micro co n-
trollers (MCUs) bri n gs I n-System-Programmabi l ity
(ISP) to Flash memory and programmable logic.
The result is a simple and flexible solution for em-
bedded designs. PSD devices combine many of
the peripheral functions found in MCU-based ap-
plications (8-bit or 16-bit), such as configurable
memories, PLD logic, and I/O.
PSD devices integrate an optimized Macrocell log-
ic architecture. The Macrocell was created to ad-
dress the unique requirements of embedded
system designs. It allows direct connection be-
tween the system address/ data bus, and the int er-
nal PSD registers, to simplify communication
between the MCU and other supporting devices.
The PSD family offers two methods to program the
PSD Flash memory while the PSD is sold ered to
the circuit board: In-System Programming (ISP)
via JTAG, and In-Application Programming (IAP).
In-System Pr ogrammi ng (ISP) via JTAG
An IEEE 1149.1 compliant JTAG In-System Pro-
gramming (ISP) interface is included o n the PSD
enabling the en tire dev ice (Flas h m emories, PLD,
configuration) to be rapidly programmed whi le sol -
dered to the circuit board. This requires no MCU
participation, which means the PSD can be pro-
grammed anytime, even when com pletely blank.
The innovative J T AG interface to Flash mem ories
is an industry first, solving key problems faced by
designers and manuf acturin g houses, such as:
First time programming. How do I get firmware
into the Flash memory the very first time? JTAG is
the answer. Program the blank PS D with no MCU
involvement.
Inventory build-up of pre-programmed devic-
es. How do I maintain an accurate count of pre-
programmed Flash memory and PLD devices
based on customer demand? How many and what
version? JTAG is t he answer. Build your hardware
with blank PSDs soldered directly to the board and
then custom program just before they are shipped
to the custome r. No more labels on chips, and no
more wasted inventory.
Expensive sockets. How do I eliminate the need
for expensive and unreliable sockets? JTAG is the
answer. Solder the PSD directly to the circuit
board. Program first time and subsequent times
with JTAG. No need to handle devices and b end
the fragile leads.
In-Application Programming (IAP)
Two independent Flash memory arrays are includ-
ed so that the MCU can execute code from one
while erasing a nd program m ing the o the r. Robust
product firm ware updat es in the f iled are possible
over any communication channel (e.g., CAN,
Ethernet, UART, J1850) using this unique archi-
tecture. Designers are relieved of th ese problems:
Simultaneous READ and WRITE to Flash mem-
ory. How can the MCU program the same memo-
ry from which it executing code? It cannot. The
PSD allows the MCU to operate the two Flash
memory blocks concurrently, reading code from
one while erasing and programming the ot her dur-
ing IAP.
Compl ex memory mappi ng. How can I map
these two memories efficiently? A programmable
Decode PLD (DPLD) is embedded in the PSD
MODULE. The concurrent PSD me mories can be
mapped anywhere in MCU address space, seg-
ment by segment with ext remely high address res-
olution. As an option, the secondary Flash
memory can be swapped ou t of the s ystem mem-
ory map when IAP is complete. A built-in page reg-
ister breaks t he M CU address limit.
Separa te Program an d Data space. How can I
write to Flash m em ory while it reside s in Program
space during field firmware updates? My
80C51XA will not allow it. The PSD provides
means t o reclassify F lash m em ory as Data space
during IAP, then back to Program space when
complete.
PSDsoft
PSDsoft, a software development tool from ST,
guides you through the design process step-by-
step making it poss ible to complete an embed ded
MCU design capable of ISP/IAP in just hours. Se-
lect your MCU and PSDsof t t akes you through the
remainder of the design with point and click entry,
covering PSD selection, pin definitions, program-
mable logic inputs and output s, MCU memory map
definition, ANS I-C code generat ion for you r MCU,
and merging your MCU f irmware wi th the PSD de-
sign. When complete, two different device pro-
grammers are supported directly from PSDsoft:
FlashLINK ( JTAG) and PSDpro.