FX2LP unable to access more than 8kB RAM | Cypress Semiconductor
FX2LP unable to access more than 8kB RAM
I have purchased three FX2LP development boards for hobby use from e-bay. These are sold as:
EZ-USB FX2LP CY7C68013A USB Development Core Board Logic Analyzer EEPROM
Any documentation I find says these chips have 16kB RAM, but I can only access bottom 8kB, the range 0x0000 to 0x1fff. Any writes to RAM region 0x2000 to 0x3fff are ignored. Reads seem to return back the same 16bit value for any address. This happens with both 0xA0 vendorcode over USB and executing 8051 program code.
If my build toolchain places descriptors at over 0x2000, the device will disconnect and renumerate, but fails to setup USB with new descriptors. Same code with descriptors moved below 0x2000 works as expected.
Markings on the boards and chips I have:
LCSOFT CY7C68013A MINI BOARD
B 04 PHI 1125
Can you tell if these markings are valid for Cypress manufactured chips and if there is any related errata with the revision?
Is there some (un)documented bootstrap that could explain this behaviour?