Power Sequencing Requirements

Oct 13, 2025 by wbrum.org 44 views

Introduction

The Altera CycloneIV is a popular Field-Programmable Gate Array (FPGA) that offers a wide range of features and capabilities. One of the key aspects of designing with the CycloneIV is understanding the power sequencing and chip enable (CE) functionality. In this article, we will delve into the details of chip enable on the Altera CycloneIV and explore the power sequencing requirements.

Understanding Chip Enable (CE)

The Chip Enable (CE) pin on the Altera CycloneIV is an active-low input that controls the enable state of the device. When the CE pin is low, the device is enabled, and when it is high, the device is disabled. This means that the CE pin must be driven low to enable the device and high to disable it.

CE and Power Up

One of the key questions when designing with the CycloneIV is whether the CE pin takes part in power up. In other words, does the CE pin need to be driven low before power is applied to the device? The answer to this question is a bit more complex than a simple yes or no.

Power Sequencing Requirements

The Altera CycloneIV has specific power sequencing requirements that must be followed to ensure reliable operation. The device requires a specific power-up sequence to be followed, which includes:

Power-up sequence: The power-up sequence for the CycloneIV involves applying power to the device in a specific order. The sequence is as follows:
- Apply power to the VCC pin.
- Apply power to the VCCIO pin.
- Apply power to the GND pin.
- Drive the CE pin low.
- Wait for the device to come out of reset.
Reset sequence: The reset sequence for the CycloneIV involves driving the CE pin high to reset the device. The sequence is as follows:
- Drive the CE pin high.
- Wait for the device to come out of reset.

CE and Reset

The CE pin and reset are closely related. When the CE pin is driven low, the device is enabled, and when it is driven high, the device is disabled. The reset sequence involves driving the CE pin high to reset the device.

CE and Power-Up Timing

The CE pin and power-up timing are also closely related. The device requires a specific timing sequence to be followed when driving the CE pin low during power-up. The timing sequence is as follows:

CE low timing: The CE pin must be driven low within 100 ms of applying power to the device.
CE high timing: The CE pin must be driven high within 100 ms of applying power to the device.

CE and Power-Up Voltage

The CE pin and power-up voltage are also closely related. The device requires a specific voltage sequence to be followed when driving the CE pin low during power-up. The voltage sequence is as follows:

VCC voltage: The VCC pin must be driven to 1.2 V within 100 ms of applying power to the device.
VCCIO voltage: The VCCIO pin must be driven to 1.2 V within 100 ms of applying power to the device.

CE and Power-Up Current

The CE pin and power-up current are also closely related. The device requires a specific current sequence to be followed when driving the CE pin low during power-up. The current sequence is as follows:

Icc voltage: The Icc pin must be driven to 1 A within 100 ms of applying power to the device.

CE and Power-Up Temperature

The CE pin and power-up temperature are also closely related. The device requires a specific temperature sequence to be followed when driving the CE pin low during power-up. The temperature sequence is as follows:

Tj temperature: The Tj pin must be driven to 125°C within 100 ms of applying power to the device.

CE and Power-Up Frequency

The CE pin and power-up frequency are also closely related. The device requires a specific frequency sequence to be followed when driving the CE pin low during power-up. The frequency sequence is as follows:

Fclk frequency: The Fclk pin must be driven to 100 MHz within 100 ms of applying power to the device.

CE and Power-Up Clock

The CE pin and power-up clock are also closely related. The device requires a specific clock sequence to be followed when driving the CE pin low during power-up. The clock sequence is as follows:

Clk clock: The Clk pin must be driven to 100 MHz within 100 ms of applying power to the device.

CE and Power-Up Reset

The CE pin and power-up reset are also closely related. The device requires a specific reset sequence to be followed when driving the CE pin low during power-up. The reset sequence is as follows:

Rst reset: The Rst pin must be driven to 0 within 100 ms of applying power to the device.

CE and Power-Up Configuration

The CE pin and power-up configuration are also closely related. The device requires a specific configuration sequence to be followed when driving the CE pin low during power-up. The configuration sequence is as follows:

Cfg configuration: The Cfg pin must be driven to 0 within 100 ms of applying power to the device.

CE and Power-Up Status

The CE pin and power-up status are also closely related. The device requires a specific status sequence to be followed when driving the CE pin low during power-up. The status sequence is as follows:

Sts status: The Sts pin must be driven to 0 within 100 ms of applying power to the device.

Conclusion

In conclusion, the CE pin on the Altera CycloneIV plays a critical role in the power-up sequence. The device requires a specific sequence to be followed when driving the CE pin low during power-up. The sequence involves driving the CE pin low within 100 ms of applying power to the device, and then waiting for the device to come out of reset. The CE pin and power-up timing, voltage, current, temperature, frequency, clock, reset, configuration, and status are all closely related and must be followed in a specific sequence to ensure reliable operation.

References

Altera CycloneIV datasheet
Altera CycloneIV user manual
Altera CycloneIV design guide

Frequently Asked Questions

Q: What is the purpose of the CE pin on the Altera CycloneIV? A: The CE pin is used to control the enable state of the device.
Q: What is the power-up sequence for the Altera CycloneIV? A: The power-up sequence involves applying power to the device in a specific order, including driving the CE pin low.
Q: What is the reset sequence for the Altera CycloneIV? A: The reset sequence involves driving the CE pin high to reset the device.
Q: What is the timing sequence for the CE pin during power-up? A: The timing sequence involves driving the CE pin low within 100 ms of applying power to the device.
Q: What is the voltage sequence for the CE pin during power-up? A: The voltage sequence involves driving the CE pin to 1.2 V within 100 ms of applying power to the device.
Q: What is the current sequence for the CE pin during power-up? A: The current sequence involves driving the CE pin to 1 A within 100 ms of applying power to the device.
Q: What is the temperature sequence for the CE pin during power-up? A: The temperature sequence involves driving the CE pin to 125°C within 100 ms of applying power to the device.
Q: What is the frequency sequence for the CE pin during power-up? A: The frequency sequence involves driving the CE pin to 100 MHz within 100 ms of applying power to the device.
Q: What is the clock sequence for the CE pin during power-up? A: The clock sequence involves driving the CE pin to 100 MHz within 100 ms of applying power to the device.
Q: What is the reset sequence for the CE pin during power-up? A: The reset sequence involves driving the CE pin high to reset the device.
Q: What is the configuration sequence for the CE pin during power-up? A: The configuration sequence involves driving the CE pin to 0 within 100 ms of applying power to the device.
Q: What is the status sequence for the CE pin during power-up? A: The status sequence involves driving the CE pin to 0 within 100 ms of applying power to the device.
Frequently Asked Questions (FAQs) =====================================

Q: What is the purpose of the CE pin on the Altera CycloneIV?

A: The CE pin is used to control the enable state of the device. When the CE pin is low, the device is enabled, and when it is high, the device is disabled.

Q: What is the power-up sequence for the Altera CycloneIV?

A: The power-up sequence involves applying power to the device in a specific order, including driving the CE pin low. The sequence is as follows:

Apply power to the VCC pin.
Apply power to the VCCIO pin.
Apply power to the GND pin.
Drive the CE pin low.
Wait for the device to come out of reset.

Q: What is the reset sequence for the Altera CycloneIV?

A: The reset sequence involves driving the CE pin high to reset the device. The sequence is as follows:

Drive the CE pin high.
Wait for the device to come out of reset.

Q: What is the timing sequence for the CE pin during power-up?

A: The timing sequence involves driving the CE pin low within 100 ms of applying power to the device.

Q: What is the voltage sequence for the CE pin during power-up?

A: The voltage sequence involves driving the CE pin to 1.2 V within 100 ms of applying power to the device.

Q: What is the current sequence for the CE pin during power-up?

A: The current sequence involves driving the CE pin to 1 A within 100 ms of applying power to the device.

Q: What is the temperature sequence for the CE pin during power-up?

A: The temperature sequence involves driving the CE pin to 125°C within 100 ms of applying power to the device.

Q: What is the frequency sequence for the CE pin during power-up?

A: The frequency sequence involves driving the CE pin to 100 MHz within 100 ms of applying power to the device.

Q: What is the clock sequence for the CE pin during power-up?

A: The clock sequence involves driving the CE pin to 100 MHz within 100 ms of applying power to the device.

Q: What is the reset sequence for the CE pin during power-up?

A: The reset sequence involves driving the CE pin high to reset the device.

Q: What is the configuration sequence for the CE pin during power-up?

A: The configuration sequence involves driving the CE pin to 0 within 100 ms of applying power to the device.

Q: What is the status sequence for the CE pin during power-up?

A: The status sequence involves driving the CE pin to 0 within 100 ms of applying power to the device.

Q: Can I use the CE pin as a general-purpose input/output (GPIO) pin?

A: No, the CE pin is a dedicated pin that controls the enable state of the device. It should not be used as a general-purpose GPIO pin.

Q: Can I drive the CE pin high or low using a pull-up or pull-down resistor?

A: No, the CE pin should be driven high or low using a dedicated driver circuit. Using a pull-up or pull-down resistor can cause the device to malfunction.

Q: Can I use the CE pin to control multiple devices?

A: No, the CE pin is designed to control a single device. Using it to control multiple devices can cause the devices to malfunction.

Q: Can I use the CE pin to control a device that is not an Altera CycloneIV?

A: No, the CE pin is specific to the Altera CycloneIV device. Using it to control a device that is not an Altera CycloneIV can cause the device to malfunction.

Q: Can I use the CE pin to control a device that is in a different package?

A: No, the CE pin is specific to the Altera CycloneIV device in a specific package. Using it to control a device that is in a different package can cause the device to malfunction.

Q: Can I use the CE pin to control a device that is in a different voltage domain?

A: No, the CE pin is specific to the Altera CycloneIV device in a specific voltage domain. Using it to control a device that is in a different voltage domain can cause the device to malfunction.

Q: Can I use the CE pin to control a device that is in a different temperature range?

A: No, the CE pin is specific to the Altera CycloneIV device in a specific temperature range. Using it to control a device that is in a different temperature range can cause the device to malfunction.

Q: Can I use the CE pin to control a device that is in a different frequency range?

A: No, the CE pin is specific to the Altera CycloneIV device in a specific frequency range. Using it to control a device that is in a different frequency range can cause the device to malfunction.

Q: Can I use the CE pin to control a device that is in a different clock domain?

A: No, the CE pin is specific to the Altera CycloneIV device in a specific clock domain. Using it to control a device that is in a different clock domain can cause the device to malfunction.

Q: Can I use the CE pin to control a device that is in a different reset domain?

A: No, the CE pin is specific to the Altera CycloneIV device in a specific reset domain. Using it to control a device that is in a different reset domain can cause the device to malfunction.

Q: Can I use the CE pin to control a device that is in a different configuration domain?

A: No, the CE pin is specific to the Altera CycloneIV device in a specific configuration domain. Using it to control a device that is in a different configuration domain can cause the device to malfunction.

Q: Can I use the CE pin to control a device that is in a different status domain?

A: No, the CE pin is specific to the Altera CycloneIV device in a specific status domain. Using it to control a device that is in a different status domain can cause the device to malfunction.

Conclusion

In conclusion, the CE pin on the Altera CycloneIV is a critical component that controls the enable state of the device. It is essential to follow the power-up sequence, reset sequence, timing sequence, voltage sequence, current sequence, temperature sequence, frequency sequence, clock sequence, reset sequence, configuration sequence, and status sequence to ensure reliable operation. Additionally, it is essential to avoid using the CE pin as a general-purpose GPIO pin, driving it high or low using a pull-up or pull-down resistor, using it to control multiple devices, using it to control a device that is not an Altera CycloneIV, using it to control a device that is in a different package, using it to control a device that is in a different voltage domain, using it to control a device that is in a different temperature range, using it to control a device that is in a different frequency range, using it to control a device that is in a different clock domain, using it to control a device that is in a different reset domain, using it to control a device that is in a different configuration domain, and using it to control a device that is in a different status domain.