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STMicroelectronics PSD834F2V-20MI
- Part No.:
- PSD834F2V-20MI
- Manufacturer:
- STMicroelectronics
- Category:
- Specialized ICs
- Package:
- 52-QFP
- Datasheet:
-
PSD834F2V-20MI.pdf
- Description:
- IC PROG PERIPH IC 52PQFP
- Quantity:
- Payment:
- Shipping:
Inventory:4,236
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Product details
Overview
PSD834F2V-20MI from STMicroelectronics is a Flash Programmable System Device (PSD) integrating 2 Mbit primary Flash, 256 Kbit secondary Flash, 64 Kbit battery-backed SRAM, a 16-output CPLD, a 73-input/17-output DPLD, and 27 reconfigurable I/O ports - all optimized for direct interfacing with 8-bit MCUs such as Intel 8051, Motorola 68HC12, and Zilog Z80. It supports in-system programming via JTAG and enables concurrent code execution and Flash update.
For engineers reviewing the PSD834F2V-20MI datasheet, PSD834F2V-20MI pinout, PSD834F2V-20MI application, or PSD834F2V-20MI equivalent, key selection criteria include its dual-Flash architecture with independent sector erase, 256× address space expansion via page register, JTAG-based ISP capability, and programmable power management with 25 µA standby current.
Technical Context
The PSD834F2V implements a tightly coupled MCU peripheral architecture where the DPLD decodes address ranges to select memory blocks (primary Flash, secondary Flash, SRAM) and registers, while the CPLD provides user-programmable logic with 16 OMCs and 24 IMCs for state machines, counters, or bus control. Both PLDs share a common 73-signal input bus derived from MCU address/data/control lines.
Its MCU bus interface auto-detects multiplexed or non-multiplexed timing, latching addresses on ALE and responding to RD/WR/CS without external glue logic. The Page Register (8-bit) enables dynamic remapping of Flash sectors across 256 pages, supporting robust in-application programming (IAP) by executing from secondary Flash while updating primary Flash.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Primary Flash | 2 Mbit (256K × 8), 8 uniform sectors - enables selective erase/write without disturbing adjacent firmware sections. |
| Secondary Flash | 256 Kbit (32K × 8), 4 uniform sectors - dedicated boot/data memory allowing concurrent code execution and primary Flash update. |
| SRAM | 64 Kbit battery-backed - retains critical runtime data during main power loss when VSTBY (PC2) is connected to backup source. |
| CPLD Capacity | 16 output macrocells + 24 input macrocells - sufficient for address decoding extensions, peripheral enable logic, or custom state machines. |
| DPLD Function | 73 inputs / 17 outputs / 42 product terms - hardwired to generate sector-select signals for all internal memory blocks and registers. |
| JTAG ISP Support | Full-chip programming via TMS/TCK/TDI/TDO on Port C - eliminates need for external programmer or boot EPROM. |
| Power Management | 25 µA standby current; automatic power-down triggered by MCU inactivity - extends battery life in portable embedded systems. |
| Endurance | 100,000 Flash erase/write cycles; 1,000 PLD configuration cycles - ensures field-upgrade reliability over product lifetime. |
Pinout & Package
PSD834F2V-20MI is available in PQFP52 (M) and PLCC52 (J) packages. This variant uses the PQFP52 package with 52 leads, 0.65 mm pitch, and standard JEDEC footprint.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| PA0–PA7 | Port A I/O | 8-bit bidirectional port configurable as MCU I/O, PLD I/O, or latched address output for multiplexed buses. |
| PB0–PB7 | Port B I/O | 8-bit bidirectional port supporting same modes as Port A; can combine with Port A as 16-bit data bus for non-multiplexed MCUs. |
| PC0–PC7 | Port C I/O | Includes JTAG pins (PC0=TMS, PC1=TCK, PC3=TSTAT, PC4=TERR, PC5=TDI, PC6=TDO); also supports VSTBY (PC2) for SRAM battery backup. |
| PD0–PD2 | Port D I/O | 3-bit port; PD2 serves as Chip Select Input (CSI), enabling PSD selection in multi-peripheral MCU systems. |
| AD0–AD15 | Multiplexed Address/Data Bus | 16-bit bidirectional bus compatible with Intel 80x86-style multiplexed interfaces; latched internally on ALE. |
| CLKIN (PD1) | Input Clock | Accepts external clock up to 20 MHz; drives internal timing for Flash access, PLD operation, and JTAG interface. |
| RD, WR, ALE, CS | MCU Control Signals | Directly interface with 8-bit MCU control bus; used for memory read/write strobes and address latch enable. |
Key Features
| Feature | Design Value |
|---|---|
| Page Register | 8-bit register expands MCU address space by factor of 256 - enables seamless access to >64 KB memory without bank switching hardware. |
| In-System Programming (ISP) | JTAG serial interface allows full-device programming in final PCB - eliminates socketed programming and reduces manufacturing test complexity. |
| Dual-Flash Architecture | Independent primary and secondary Flash blocks - permits safe firmware updates by running bootloader from secondary Flash while rewriting primary Flash. |
| Configurable I/O Ports | 27 individually programmable pins across four ports - supports mixed-mode operation (e.g., Port A as address latch, Port C as JTAG, Port D as chip select). |
| Programmable Power Management Unit (PMU) | Automatic power-down mode triggered by MCU inactivity - reduces active current to 25 µA, ideal for battery-powered remote sensors and controllers. |
Applications
| Industrial PLC I/O Expansion | Medical Device Firmware Update |
|---|---|
|
Use Scenario: Adding isolated digital I/O and local logic to an 8051-based programmable logic controller without external address decoders or memory buffers. IC Role / Device Role / Timing Role: Acts as unified memory + logic peripheral - handles address decoding (DPLD), stores firmware (primary Flash), retains calibration data (SRAM), and implements safety interlocks (CPLD). Use Value: Reduces BOM count by replacing discrete Flash, SRAM, and PAL components; enables field firmware patching via JTAG without disassembly. |
Use Scenario: Enabling secure, verified firmware updates in battery-powered patient monitors where power interruption must not corrupt stored algorithms or sensor calibration. IC Role / Device Role / Timing Role: Provides dual-Flash IAP capability - executes clinical measurement routines from secondary Flash while validating and writing new firmware to primary Flash under watchdog supervision. Use Value: Guarantees atomic firmware updates with rollback support; SRAM retention via VSTBY (PC2) preserves real-time settings during brief AC loss. |
| Automotive Body Control Module | Legacy Industrial HMI Controller |
|
Use Scenario: Replacing aging EPROM+PAL designs in door module controllers requiring CAN-linked diagnostics and EEPROM-like field updates. IC Role / Device Role / Timing Role: Integrates non-volatile storage (Flash), volatile working memory (SRAM), and custom logic (CPLD) for window lift sequencing, anti-pinch logic, and wake-on-CAN detection. Use Value: Eliminates external 5V-to-3.3V level shifters and timing-critical glue logic; 100,000 Flash cycles support 15-year vehicle service life with periodic calibration updates. |
Use Scenario: Modernizing Z80-based human-machine interface panels in factory HMIs where legacy software must run unchanged but hardware requires RoHS compliance and extended temperature support. IC Role / Device Role / Timing Role: Emulates original memory map and bus timing - presents identical 16-bit address/data interface with same RD/WR/CS timing, while adding JTAG debug and in-field reprogramming. Use Value: Enables drop-in replacement of obsolete EPROM/PAL combinations; maintains backward compatibility while adding security features like Flash lock bits and JTAG disable. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar programmable system device applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| Cypress CY8C29466-24PVXI | PSOC-based mixed-signal array with integrated ADC, op-amps, and ARM M8C core - no native Flash/SRAM integration; requires external memory for code storage. | Targets analog-intensive control (e.g., motor sensing), not memory/logic consolidation for 8-bit MCUs. | Select only if system requires on-chip analog peripherals and can accommodate external Flash boot loader. |
| Microchip PIC18F87J11 | 8-bit MCU with 128 KB Flash, 4 KB RAM, and limited programmable logic (CLC modules) - lacks dual-Flash IAP, battery-backed SRAM, and dedicated DPLD for address decoding. | Suitable for self-contained control tasks but cannot replace discrete Flash+PLD+SRAM subsystems in legacy 8-bit designs. | Choose when consolidating processing and basic logic, not when extending existing MCU bus with memory/peripheral functions. |
Compared with CY8C29466-24PVXI and PIC18F87J11, PSD834F2V-20MI uniquely delivers co-packaged Flash, SRAM, and dual-purpose PLDs with native 8-bit bus timing - making it the only option for retrofitting legacy MCU systems with field-upgradable firmware and hardware-defined logic without redesigning the bus interface.
Availability
PSD834F2V-20MI is available at Aetrix Electronics and suitable for industrial PLC I/O expansion, medical device firmware update, automotive body control modules, and legacy HMI controller modernization requiring stable component supply and long-term lifecycle support.
Supply support for PSD834F2V-20MI includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
STMicroelectronics is a global semiconductor leader headquartered in Geneva, specializing in microcontrollers, power management, and embedded flash solutions for industrial, automotive, and consumer markets.
The PSD family was designed specifically to replace discrete Flash, SRAM, and PLD components in 8-bit MCU systems - delivering single-chip memory + logic integration with JTAG-based field programmability and power-aware operation.
FAQ
What MCU families does PSD834F2V-20MI directly support?
PSD834F2V-20MI natively interfaces with Intel 8031/8051XA/80186/80386EX, Motorola 68HC11/68HC12/683XX, Philips 8031, and Zilog Z80/Z8 MCUs. Its bus logic auto-adapts to multiplexed (ALE-driven) or non-multiplexed timing, eliminating external address latches or wait-state generators required by discrete memory chips.
How does dual-Flash architecture enable safe in-application programming (IAP)?
The 256 Kbit secondary Flash operates as a dedicated boot/code-execution memory. During IAP, the MCU runs firmware from secondary Flash while issuing erase/write commands to the 2 Mbit primary Flash - ensuring continuous system operation and preventing corruption from power loss mid-update. Sector-level erase granularity further isolates updates to specific firmware modules.
Can the CPLD and DPLD be programmed independently, and what tools are required?
Yes - the DPLD (address decoder) and CPLD (user logic) are programmed separately using ST's PSDsoft Express tool. The DPLD configuration is generated automatically from memory mapping settings, while the CPLD accepts ABEL or VHDL netlists. Both are loaded via JTAG (TMS/TCK/TDI/TDO on Port C) or in-system via MCU-executed algorithms from SRAM or secondary Flash.
What is the role of the Page Register, and how does it affect memory addressing?
The 8-bit Page Register extends the MCU's 16-bit address space to 24 bits by prepending its value to AD0–AD15. This allows mapping of Flash sectors, SRAM, or registers into disjoint 64 KB windows - essential for IAP (e.g., loading new firmware into page 0x05 while executing from page 0x01) and simplifying memory management in resource-constrained 8-bit systems.
PSD834F2V-20MI Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- -
- Package/Case:
- 52-QFP
- Packaging:
- Tray
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Type:
- Programmable Peripherals IC
- Applications:
- 8-Bit MCU Peripherals
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 52-PQFP (10x10)
- Grade:
- -
- Qualification:
- -
PSD834F2V-20MI FAQ
1.How can I place an order for PSD834F2V-20MI through Aetrix?
Please submit a Request for Quotation (RFQ) for PSD834F2V-20MI on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for PSD834F2V-20MI reliable?
The price and inventory of PSD834F2V-20MI are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for PSD834F2V-20MI is usually 5 days.
3.What payment methods are accepted for PSD834F2V-20MI?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for PSD834F2V-20MI transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for PSD834F2V-20MI?
PSD834F2V-20MI orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your PSD834F2V-20MI order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for PSD834F2V-20MI?
For technical support, including PSD834F2V-20MI datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your PSD834F2V-20MI requirements.
6.How does Aetrix verify that PSD834F2V-20MI is sourced from the original manufacturer or authorized distributors?
All PSD834F2V-20MI products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that PSD834F2V-20MI meets industry standards.
7.What is the process for return or replacement of PSD834F2V-20MI?
All PSD834F2V-20MI units undergo pre-shipment inspection (PSI). If there is an issue with PSD834F2V-20MI, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The PSD834F2V-20MI part is unused and in its original packaging.
Return procedure for PSD834F2V-20MI:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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