Pin D6 on the FS48 package and pin 38 on the VO48 package are VCCO pins, but were mis-labelled as VCCINT pins in the original DS123 v2.0 data sheet.
If the board layout was not corrected and pin D6 on FS48 or pin 38 on VO48 is tied to VCCint (1.8V) and VCCO is powered to 3.3V, JTAG erase and programming operations might not be functional.
Pin D6 on the FS48 package and pin 38 on the VO48 package must be connected to VCCO.
A new version (v2.1) of the Platform Flash PROM data sheet (DS123) was released to xilinx.com on 11/18/2003 with pinout corrections for all 8Mb, 16Mb, and 32Mb Platform Flash PROM-packages that include:
(The XCFxxS-VO20 PROM-package pinouts are NOT affected by this data sheet revision.)
The DS123, v2.1, data sheet revisions specifically include corrections to the XCFxxP Pinout tables and corresponding pinout figures:
For VO48 package, removed 38 from VCCINT and added it to VCCO.
For FS48 package, removed pin D6 from VCCINT and added it to VCCO.
Table 13 (FS48 package):
For pin D6, changed name from VCCINT to VCCO.
Figure 18 (VO48 package): For pin 38, changed name from VCCINT to VCCO.