
EZ-USB FX2 Technical Reference Manual
Page 3-6 EZ-USB FX2 Technical Reference Manual v2.1
3.4.3 Serial EEPROM Present, First Byte is 0xC2
If, at power-on reset, the FX2 detects an EEPROM connected to its I²C-compatible with the value
0xC2 at address 0, the FX2 loads the EEPROM data into RAM. It also sets the RENUM bit to 1,
causing device requests to be handled by the firmware instead of the Default USB Device. The
“C2 Load” EEPROM data format is shown in Table3-5.
The first byte indicates a “C2 load”, which instructs the FX2 to copy the EEPROM data into RAM.
The FX2 reads the next six bytes (VID / PID / DID) even though they aren’t used by most C2-Load
applications. The eighth byte (byte 7) is the configuration byte described in the previous section.
Table 3-5. “C2 Load” Format
EEPROM Address Contents
0
0xC2
1 Vendor ID (VID) L
2 Vendor ID (VID) H
3 Product ID (PID) L
4 Product ID (PID) H
5 Device ID (DID) L
6 Device ID (DID) H
7 Configuration byte
8 Length H
9 Length L
10 Start Address H
11 Start Address L
--- Data Block
---
--- Length H
--- Length L
--- Start Address H
--- Start Address L
--- Data Block
---
--- 0x80
--- 0x01
--- 0xE6
--- 0x00
last 00000000
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