SCPS287A November 2023 – September 2024 TPLD1201
ADVANCE INFORMATION
Refer to the PDF data sheet for device specific package drawings
The TPLD1201 has a power-on reset (POR) macro-cell that provides correct device initialization and operation of all macro-cells in the device. The purpose of the POR circuit is to have consistent behavior and predictable results when the VCC power is first ramping to the device, and also while the VCC is falling during power-down. To accomplish this goal, the POR drives a defined sequence of internal events that trigger changes to the states of different macro-cells inside the device, and finally to the state of the I/O pins.
The power-on Reset (POR) macro-cell will produce a logic High signal as an output when the device power supply (VCC) rises to approximately VPORR and device completely starts up. All outputs are in high impedance state and chip starts loading data from OTP. The reset signal is released for internal macro-cells and all the registers are initialized to their default states. Figure 7-21 shows POR system generates a sequence of signals that enable certain macro-cells.
As shown in Figure 7-21, after the VCC has start ramping up and crosses the VPORR threshold:
Delay blocks will pass their inputs through to the output during the startup sequence without delaying the signal per the configuration, so a LUT added in front of the input of a DLY that ANDs the DLY input with POR will cause the input signal to not appear until the device has fully powered up.
GPIO quick charge: There is an option to connect a 2kΩ resistor in parallel to any configured pull up/pull down resistors to help inputs get to the right voltage faster, especially if there is significant capacitance. The 10kΩ, 100kΩ and 1MΩ GPIO pull up/pull down resistors are not enabled until the POR sequence is completed.
Initialization: All internal macro-cells are initialized to a low level by default. Starting from when VCC exceeds VPORR, macro-cells in the TPLD1201 are powered on and forced into a reset state.
The VREF output pin driving signal can precede POR output signal going high by 3µs to 5µs. The POR signal going high indicates the mentioned power-up sequence is complete.