Answers Database

PROMs: Atmel EEPROM compatibility with Xilinx 1700 series


Record #1023

Product Family:  Hardware

Product Line:  1700

Problem Title:
PROMs:	Atmel EEPROM compatibility with Xilinx 1700 series


Problem Description:
Atmel makes EEPROM-based devices that they claim are pin compatible
with Xilinx 1700 devices.  They are named in a similar fashion as Xilinx
PROMs-- 17Cxxx-- 17C65, 17C128, for example.  Although they are pin-
compatible, they are not design-compatible.

 Xilinx has not qualified these parts for use in configuring Xilinx FPGAs.


Solution 1:

Although the Atmel parts are spec'd the same, there are some significant
differences between the Atmel EEPROMs and Xilinx serial PROMs:

1. Atmel PROMs are not compatible with Xilinx FPGA Express Mode configuration
because they are not fast enough.

2. There is incompatibility in how pin 7 (VPP), the programming voltage
pin, is connected to Vcc.  During operation, this pin must be connected to
VCC for Xilinx serial PROMs.  Atmel uses the same pin as an active low serial
enable input for in system reprogramming.  Because of this difference, the
Atmel parts are not drop in replacements.




End of Record #1023