PSD4235G2V-10U STMICROELECTRONICS [STMicroelectronics], PSD4235G2V-10U Datasheet - Page 9

• Manufacturer Part Number: PSD4235G2V-10U
• Description: Flash In-System Programmable (ISP) Peripherals for 16-bit MCUs
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

SUMMARY DESCRIPTION
The PSD family of memory systems for microcon-
trollers (MCUs) brings In-System-Programmability
(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.
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 inter-
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 soldered to
the circuit board: In-System Programming (ISP)
via JTAG, and In-Application Programming (IAP).
In-System Programming (ISP) via JTAG
An IEEE 1149.1 compliant JTAG In-System Pro-
gramming (ISP) interface is included on the PSD
enabling the entire device (Flash memories, PLD,
configuration) to be rapidly programmed while sol-
dered to the circuit board. This requires no MCU
participation, which means the PSD can be pro-
grammed anytime, even when completely blank.
The innovative JTAG interface to Flash memories
is an industry first, solving key problems faced by
designers and manufacturing 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 PSD 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 the answer. Build your hardware
with blank PSDs soldered directly to the board and
then custom program just before they are shipped
to the customer. 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
This is preliminary information on a new product now in development or undergoing evaluation. Details are subject to change without notice.
with JTAG. No need to handle devices and bend
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 and programming the other. Robust
product firmware updates in the filed are possible
over any communication channel (e.g., CAN,
Ethernet, UART, J1850) using this unique archi-
tecture. Designers are relieved of these 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 other dur-
ing IAP.
Complex memory mapping. How can I map
these two memories efficiently? A programmable
Decode PLD (DPLD) is embedded in the PSD
MODULE. The concurrent PSD memories can be
mapped anywhere in MCU address space, seg-
ment by segment with extremely high address res-
olution. As an option, the secondary Flash
memory can be swapped out of the system mem-
ory map when IAP is complete. A built-in page reg-
ister breaks the MCU address limit.
Separate Program and Data space. How can I
write to Flash memory while it resides in Program
space
80C51XA will not allow it. The PSD provides
means to reclassify Flash memory 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 possible to complete an embedded
MCU design capable of ISP/IAP in just hours. Se-
lect your MCU and PSDsoft takes you through the
remainder of the design with point and click entry,
covering PSD selection, pin definitions, program-
mable logic inputs and outputs, MCU memory map
definition, ANSI-C code generation for your MCU,
and merging your MCU firmware with the PSD de-
sign. When complete, two different device pro-
grammers are supported directly from PSDsoft:
FlashLINK (JTAG) and PSDpro.
during
field
firmware
PSD4256G6V
updates?
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