Article Details

ID: 3249
Case Type: faq
Category: Customer Board Design
Related To: Board Debug
Family: MachXO2

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MachXO2/XO3: In the WISHBONE Design Tips section of TN1205, Using User Flash Memory and Hardened Control Functions in MachXO2 Devices, it is stated that "EFB requires the MachXO2internal oscillator to be enabled even if it is not the source of the WISHBONE Clock." Why and where does EFB need the oscillator in WISHBONE clock generation?

When OSC is off, the user can access limited EFB features such as:
  • SPI \u2014 User Slave or User Master
  • I2C \u2014 After SDA delay is turned off by setting I2C_1_CR[3:2]=11, OSC can likewise be turned off. Following this, OSC can be disabled and User Slave or User Master can operate.
  • Timer Counter \u2014 The user clock must be selected.
For using all other EFB operations, OSCH is required.