Programming and Applications of the Microchip ATF1504AS-10JU84 CPLD
The Microchip ATF1504AS-10JU84 is a high-performance, 5V-complex programmable logic device (CPLD) built on an advanced electrically erasable technology. It belongs to the ATF15xx family and is housed in an 84-pin PLCC package. With 64 macrocells and up to 68 I/O pins, it offers a flexible and robust platform for implementing a wide range of digital logic functions, from simple glue logic to more complex state machines and control systems. Its 10ns maximum pin-to-pin logic delay makes it suitable for high-speed applications.
Programming the ATF1504AS
The programming process for this CPLD is straightforward, leveraging industry-standard tools. The device is programmed using a JTAG (IEEE 1149.1) interface, which allows for in-system programming (ISP). This is a significant advantage, as the chip can be soldered onto the final printed circuit board (PCB) and then programmed, eliminating the need for separate programming sockets and enabling field updates.
The typical programming workflow involves:
1. Design Entry: The desired logic function is captured using Hardware Description Languages (HDLs) like VHDL or Verilog, or through schematic entry in a digital design environment.
2. Synthesis and Fitting: The design is synthesized into a netlist of logic gates and then fitted (placed and routed) onto the CPLD's macrocells and interconnect resources. Microchip's ATF15xx Compiler or modern tools like the Microchip Libero SoC Design Suite are used for this process.
3. Programming File Generation: The software generates a JEDEC file (`.jed`), which contains the programming data for the fuse map of the CPLD.
4. Device Programming: The JEDEC file is transferred to the CPLD using a JTAG programmer (e.g., a USB-based programmer like the ATDH1150USB) connected to the board's JTAG header.
Key Applications
The ATF1504AS-10JU84 finds use in numerous areas due to its versatility and 5V operation:
Glue Logic Integration: It is perfect for replacing multiple discrete TTL logic ICs, reducing board space, component count, and system cost while improving reliability.
Address Decoding: In microprocessor and microcontroller-based systems, it is extensively used for generating chip select and memory decoding signals.
Bus Interface and Bridging: It can act as an interface between processors and peripherals operating at different voltage levels or protocols, implementing custom bus arbitration and protocol conversion.
State Machine Control: Its predictable timing characteristics make it ideal for implementing complex finite state machines (FSMs) for system control.
Data Encoding/Decoding: It can be programmed to handle specific data manipulation tasks like parallel-to-serial conversion, encryption, or custom signal conditioning.
ICGOODFIND: The Microchip ATF1504AS-10JU84 CPLD remains a reliable and powerful solution for integrating digital logic in 5V systems. Its combination of high-speed performance, in-system programmability, and a large number of I/Os ensures its continued relevance in industrial control, telecommunications, and legacy computer system design.
Keywords: CPLD, JTAG, In-System Programming, Logic Integration, 5V Operation
