PSD4235G2-12UIT STMICROELECTRONICS [STMicroelectronics], PSD4235G2-12UIT Datasheet - Page 12

• Manufacturer Part Number: PSD4235G2-12UIT
• Description: Flash in-system programmable (ISP) peripherals for 16-bit MCUs (3.3 V supply)
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

Description
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Description
The PSD family of memory systems for microcontrollers (MCUs) brings In-System-
Programmability (ISP) to Flash memory and programmable logic. The result is a simple and
flexible solution for embedded designs. PSD devices combine many of the peripheral
functions found in MCU based applications.
PSD devices integrate an optimized macrocell logic architecture. The macrocell was created
to address the unique requirements of embedded system designs. It allows direct
connection between the system address/data bus, and the internal 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
An IEEE 1149.1 compliant JTAG in-system programming (ISP) interface is included on the
PSD enabling the entire device (Flash memories, PLD, configuration) to be rapidly
programmed while soldered to the circuit board. This requires no MCU participation, which
means the PSD can be programmed 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 devices
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 with
JTAG. No need to handle devices and bend the fragile leads.
In-application programming (IAP)
Two independent Flash memory arrays are included 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 (CAN, Ethernet, UART, J1850, etc) using this
unique architecture. Designers are relieved of these problems:
PSD4235G2V