OnSpec 90C46D ATA/ATAPI Host to Flash Media R/W Controller



OnSpec’s 90C46D is a Complete System on a Chip Solution for Interfacing industry standard flash memories and open standards like CF, SD and SD HC etc to a CF, ATA, ATAPI, or PCMCIA Host. For any custom support, contact us.

OnSpec offers reference designs, firmware, drivers, and manufacturing test software to make product development easy. OnSpec’s patented technology provide optimum throughput and superior flash media compatibility


  • Supports industry standard flash memories and open standards like CF, SD and SD HC etc.

  • Firmware controlled interface enables a ATA, ATAPI, CF, or PCMCIA Host.

  • Compatible with Microsoft Windows XP, Windows Me, Windows 2000, Windows 98, Windows 95b, Apple OS X and Linux Kernel V2.4 or later

  • Windows 2000, Windows 98/ 98SE/ 95b and Apple OS8.6 and OS9 Multi-LUN Mass Storage Class Drivers Available

  • Multiple Icons supported in Windows and Mac

  • Serial EEPROM port

  • Serial port

  • Two General Purpose Timers

  •   Watchdog Timer

  • 16 bit RISC Processor

  • Onboard ROM contains BIOS and Application code

  • Firmware upgrade using flash media

  • Programmable IOR and IOW widths

  • Optimum hardware controlled transfer for speed and scalability

  • 100-pin 14mm x 14mm QFP package (Lead Free packaging available)




Functional Description

The 90C46D is designed to connect a wide range of memory cards to a CFTM, PCMCIA, ATAPI or ATA slot. It contains the following:

  • 100-pin LQFP package

  • Serial EEPROM port

  • Host side support

  • CFTM

  • ATA



  • The 90C46D supports industry standard flash memories and open standards like CF, SD and SD HC etc. For any custom support, contact us

  •  Serial port

  •  Two General Purpose Timers

  • Watchdog Timer

  • 16 bit Processor

  • Supports 1-bit ECC for NAND, NAND MLC and NAND Big block flash media

  • Programmable read and write widths

  • OnSpec’s patent pending EDMA technology for optimum data transfer

  • Supports PIO 4 mode

  • ATA-4 spec compliant*

* – As applicable to Flash media


OnSpec 90C46D is a 100-pin LQFP package.

CF/PCMCIA/ATA Interfaces

The 90C46D provides a slave interface to a CF, PCMICA, or ATA slot.  Memory Mode, I/O Mode, and True IDE modes are supported. Please refer to Configuration Option Registers for more details.

Serial EEPROM Port

The 90C46D provides a serial interface to access external EEPROM’s. The interface is implemented using General Purpose I/O signals and can support a variety of serial EEPROM formats.

Serial port

Supports 7200 to 115.2K bauds. It is useful as a debug port and can also be used to access the EEPROM for Reads / Writes from the serial port.

General Purpose Timers

Two general-purpose timers, Timer0 and Timer1 are provided to allow firmware programmers to keep track of timeouts as well as to generate delays.

Watchdog Timer

A Watchdog Timer is provided to enable catastrophic events to interrupt the processor. The Watchdog Timer overflow causes an internal processor reset. The Processor can read the WT bit after exiting reset to determine if the WT bit is set. If it is set, a watch dog timeout occurred.

90C46D Processor

The 90C46D Processor has a built-in 16-bit processor along with a BIOS ROM. The processor operates with a specialized instruction set optimized for Mass Storage applications and CF transaction processing. The start up code for the 16-bit processor resides in a masked ROM.


The 90C46D chip comes with an Internal RAM.

Masked ROM

The Masked ROM consists of start-up code for the 90C46D processor and many other functions as listed below:

  • Power On Initialization

  • Scan for External ROM

  • CF

  • API support for CF transactions, EEPROM Interface, Memory Management etc.

  • Built-in Library functions for Flash devices

The firmware can be easily extended / expanded by using External Serial EEPROM. BIOS provides several services to facilitate this expansion code. At boot-up time, the scan services of the BIOS search for the expansion signature in Serial EEPROM as well as via the UART. For more information on this, refer to Applications section of this manual.

The BIOS API functions are designed as Software Interrupts, making it easy for enhancements. Any Interrupt can be enhanced / modified by inserting user defined function in the interrupt placeholder. When this interrupt is called by the BIOS, the user defined function gets called first so it can enhance the behavior before passing it on to the standard BIOS function call or return without passing it on.

Programmable RD and WR cycles

The external cycles to SmartMedia are software configurable

Ordering Information

Part Number




Lead free package for IDE/ATAPI to industry standard flash memories and open standards like CF, SD and SD HC etc Read Write Controller.

100 LQFP Lead Free

(RoHS Compliant)


Technical and Design-in Information

Contact: sales@siliconapps.com

Design Support (OnSpec Engineering to review if supported and can provide these services.)

  • Card Manufacturer Compatibility Testing (Software Release Notes)

  • Two Layer Board Reference Design, BOM, Schematic and Gerber

  •  Flash Media Association Contact List

  •  Memory Stick and xD Picture Card Certification and Lab Test Results


OnSpecLink® Family of Products
This product is covered by one or more of the following patents:
US Pat. 5841424, 6438638, 6832281, 6859361, 6859369
Taiwan Pat. I 222564
Other Foreign & US Patents Pending

Memory Stick Compliant Products Test Specification Extract Version1.1.00:

Certified, Reference: 20050401 (First controller in the world to get this certification)


Information in this document is provided in connection with OnSpec Electronic products. No license, express or implied, by estoppels or otherwise, to any intellectual property rights is granted by this document.  Except as provided in OnSpec Electronic’s Terms and Conditions of Sale for such products, OnSpec Electornic assumes no liability whatsoever, and OnSpec Electronic disclaims any express or implied warranty, relating to sale and/or use of OnSpec Electronic products including liability or warranties relating to fitness for a particular purpose, merchantability, or infringement or any patent, copyright or other intellectual property right.

OnSpec Electronic products are not intended for use in medical, life saving, or life sustaining applications.


OnSpecLink Is a registered trademark of OnSpec Electronic, Inc.

All trademarks are the properties of their respective owners.

Download: Product Sheet PDF Size=72KB