![]() The Due is Arduino’s first ARM-based Arduino development board. It has 54 digital input/output pins (of which 12 can be used as PWM outputs), 12 analog inputs, 4 UARTs (hardware serial ports), a 84 MHz clock, an USB OTG capable connection, 2 DAC (digital to analog), 2 TWI, a power jack, an SPI header, a JTAG header, a reset button and an erase button. It is the first Arduino board based on a 32-bit ARM core microcontroller. I hope that other members including you may present some discussion on this issue.The Arduino Due is a microcontroller board based on the Atmel SAM3X8E ARM Cortex-M3 CPU. It is a matter of happiness that the DUE Members try their best to present rational opinions along with additional reading question of Post#1, from my view point, deserves much better answer and explanation/discussion than what I have presented in Post#2. As we are proceeding with the studies and experiments of Arduino DUE, we are faced with many many conceptual questions. The data sheet of SAM3X8E is not organized and informative as the ATmega328P is. ![]() Because the Arduino DUE is readily available and comparatively not so expensive, we find here a lot of opportunities to design/interfacing hand-made logic sifters rather than using factory-made dedicated logic sifters. This is the first time we (myself and my pupils) are playing with 1.8V Core and 3.3V IO. Traditionally, we (the maintenance/training engineers, amateur designers, and later teachers) have been bearing the mind-set of seeing the electronics logic gates from 5-V TTL/CMOS perspective. Very interesting and inspiring information. There's also no reason for the internal circuitry to maintain the same sort of voltage thresholds (or hysteresis) that is expected from external pins. The value helps us comparing the noise margin level of ARM (typical 0.18V) with 5V-CMOSHC (typical NM L/NM H = 0.6V/0.7), and then to appreciate the fabrication technology that makes ARM working with such a low NM value! Why is there the need of knowing/computing the noise margin figures? The next question may arise as: SAM3X8E is working fine with the stated noise margins. ![]() Low State Noise Margin, NM L = V IL - V OL = 0.63 - 0.45 = 0.18Vįigure-1: Illustrating the noise margin situation of SAM3X8E MCU High State Noise Margin, NM H = V OH - V IH = 1.35 - 1.17 = 0.18V The SAM3X8E data sheet has not specified these parameters.īased on the values of V IL, V IH, V OL, and V OH: Noise Margin is a figure, which quantifies the maximum level of environmental noise signal that can be tolerated by the electrical/logic gate. I have a reason to know, which is to compute the 'Worst-case Noise Margins (NM L and NM H)' while the Core runs at 4 - 84 MHz speed and creates substantial amount of electrical noise. If I have to answer on behalf of the pupils, I need to wait to hear from them why they are asking me this question. I OH: Maximum current, which the output stage of the driver gate will be delivering to the driven gates when the output of this driver gate is at Logic-H state. I OL: Maximum current, which the output transistor of the driver gate will be sinking from the driven gates when the output of this driver gate is at Logic-L state. I IH: Maximum current entering into an input terminal of the driven gate, which is at Logic-H state because of its connection with the High-state output of the driver gate. I IL: Maximum current exiting from an input terminal of the driven gate, which is at Logic-L state because of its connection with the Low-state output of the driver gate. V OH: Minimum voltage at the output of the gate, which stays above the forbidden zone and is reliably recognized as Logic-H state by the driven gate. V OL: Maximum voltage at the output of the gate, which stays below the forbidden zone and is reliably recognized as Logic-L state by the driven gate. V IH: Minimum voltage at the input of the gate, which stays above the forbidden zone and is reliably recognized as Logic-H state. V IL: Maximum voltage at the input of the gate, which stays below the forbidden zone and is reliably recognized as Logic-L state. Comments, corrections, and additions are highly appreciated. The poster has prepared the following diagram for V IL, V IH, V OL, and V OH based on this article (Figure 1) and considering the Core as an LVC Logic. ![]() What are there about other parameters: V IL, V IH, V OL, V OH, I IL, I IH, I OL, and I OH for the 1.8V Core. Pupils frequently ask about the subject matter but, the data sheets (Table 45-2) of SAM3X8E has only given: V DDCORE = 1.8V.
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