PSD835G2 datasheet(9/102 Pages) STMICROELECTRONICS

9 / 102 page

9/102

PSD835G2

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.

The CPLD in the PSD devices features an opti-

mized macrocell logic architecture. The PSD mac-

rocell

was

created

address

the

unique

requirements of embedded system designs. It al-

lows direct connection between the system ad-

dress/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, 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

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 field are possible

over any communications channel (CAN, Ether-

net, UART, J1850, etc.) using this unique architec-

ture. 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 is 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.

The concurrent PSD memories can be mapped

anywhere in MCU address space, segment by

segment with extremely high address resolution.

As an option, the secondary Flash memory can be

swapped out of the system memory map when

IAP is complete. A built-in page register breaks the

MCU address limit.

Separate Program and Data space. How can I

write to Flash memory while it resides in Program

space during field firmware updates? My 80C51

will not allow it. The PSD provides means to re-

classify 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.

PSD835G2 Datasheet(PDF) 9 Page - STMicroelectronics

PSD835G2 Datasheet(HTML) 9 Page - STMicroelectronics

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL