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| Scroll pdf title |
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| title | I2C signals summary. |
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name | definition | description | SDA | serial data | This is a bidirectional pin used to transfer addresses and data into and out of a device. | SCL | serial clock | This signal is used to synchronize the data transfer to and from a device. |
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The I2C bus is typically used by the USB FX2 microcontroller to write USB firmware to the serial EEPROM. In this case,
the I2C port of the FPGA must be set in slave mode (SCL pin as input),
the device attached to the I2C port of B2B J(M)5 connector must be set to slave mode.
The USB FX2 microcontroller can operate just in I2C master mode (default operation). If the user wants to set another device attached to the I2C bus as master device, the USB FX2 microcontroller shall three-state (Z = high impedance) its SCL and SDA pins.
If the FPGA is set to I2C master mode, it can write to or read from serial EEPROM (always slave mode) and B2B connector J(M)5 (attached device set to slave mode).
If the device attached to the I2C port of B2B J(M)5 connector is set to master mode, it can write to or read from serial EEPROM (always slave mode) and FPGA I2C port (set to slave mode).
Possible I2C operation modes are summarized in the table below.
| Scroll pdf title |
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| title | I2C bus modes summary. |
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core | EZ-USB FX2LP | FPGA
(SDA = I/O) | B2B J(M)5 | serial EEPROM | default | master | slave
SCL = I | slave | slave | custom | inactive
SCL = SDA = Z | master
SCL = O | slave | slave | custom | inactive
SCL = SDA = Z | slave
SCL = I | master | slave |
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