33.7.1 Entering Programming Mode

Follow the steps below to put the device in Parallel (High-voltage) Programming mode:

  1. Set the Prog_enable pins listed in the table Pin Values Used to Enter Programming Mode above to “0x0000”, RESET pin to 0V and VCC to 0V.
  2. Apply 4.5–5.5V between VCC and GND.

    Ensure that VCC reaches at least 1.8V within the next 20μs.

  3. Wait 20–60μs, and apply 11.5–12.5V to RESET.
  4. Keep the Prog_enable pins unchanged for at least 10μs after the high voltage has been applied to ensure the Prog_enable signature has been latched.
  5. Wait at least 300μs before giving any parallel programming commands.
  6. Exit Programming mode by powering down the device or by bringing RESET pin to 0V.

If the rise time of VCC is unable to fulfill the requirements listed above, the following alternative method can be used to put the device in Parallel (High-voltage) Programming mode:

  1. Set the Prog_enable pins listed in the table Pin Values Used to Enter Programming Mode above to “0000”, RESET pin to 0V and VCC to 0V.
  2. Apply 4.5–5.5V between VCC and GND.
  3. Monitor VCC, and as soon as VCC reaches 0.9–1.1V, apply 11.5–12.5V to RESET.
  4. Keep the Prog_enable pins unchanged for at least 10μs after the high voltage has been applied to ensure the Prog_enable signature has been latched.
  5. Wait until VCC reaches 4.5–5.5V before giving any parallel programming commands.
  6. Exit Programming mode by powering down the device or by bringing RESET pin to 0V.