RP2350 Chip Flaw Causes Setbacks in Raspberry Pi's Latest Offering

RP2350 Chip Flaw Causes Setbacks in Raspberry Pi's Latest Offering

Significant Obstacle Uncovered

The tech world buzzed with excitement in August when Raspberry Pi unveiled its RP2350 microcontroller in its Pico 2 microcontroller. This quad-core dual-architecture chip, featuring RISC-V cores, was poised to be the successor to the wildly popular RP2040, which is at the heart of the Pico 1 microcontroller. However, the path to innovation is rarely smooth, and the RP2350 has encountered a significant obstacle that's causing ripples throughout the maker community.

Erratum RP2350-E9: A Flaw in the Silicon

At the heart of the issue lies a hardware fault dubbed "erratum RP2350-E9." This flaw causes general-purpose input/output (GPIO) pins to "latch" at approximately 2.15V, creating a persistent high state that refuses to return to a low state. Initially discovered and reported by Ian Lesnet of Dangerous Prototypes, this bug has proven to be more pervasive than initially thought, affecting a wide range of projects and potential applications.

Wider Implications Than Initially Reported

While Raspberry Pi's official documentation suggests that the issue only occurs when internal pull-down resistors are enabled, developers in the field are reporting a more severe and widespread problem. The latch-up appears to affect input pins even without the use of internal pull-downs, potentially triggering whenever a pin is exposed to a high state. This discrepancy between the official errata and real-world experiences has left many developers frustrated and uncertain.

Projects on Hold: The Ripple Effect

The impact of this flaw is already being felt across the maker community. Ian Lesnet has paused production on his RP2350-based Bus Pirate projects, citing concerns that the first batch may be "Dead On Arrival." Similarly, Agustín Gimenez Bernad has halted efforts to port his RP2040-based logic analyzer to the new chip. These are just two examples of the many projects now in limbo due to the RP2350's unexpected behavior.

Limited Workarounds and Their Drawbacks

While some workarounds have been proposed, such as adding external pull-down resistors or implementing software fixes, these solutions come with significant drawbacks. The need for additional components increases complexity and cost, while software fixes may severely impact performance, particularly for applications using the chip's Programmable Input/Output (PIO) features.

Raspberry Pi's Response and the Road Ahead

Raspberry Pi has acknowledged the issue and is in discussions with the IP supplier they believe to be responsible for the flaw. However, as of now, the company has not announced plans for a hardware revision to address the problem. This leaves developers in a state of uncertainty, forced to either work around the limitations or put their RP2350-based projects on hold indefinitely.

A Cautionary Tale in Chip Development

The RP2350 saga serves as a reminder of the complexities involved in semiconductor design and manufacturing. Even with extensive testing and early access programs, unforeseen issues can arise that significantly impact a product's usability. As the tech community eagerly awaits a more comprehensive solution from Raspberry Pi, this situation underscores the importance of thorough testing and transparent communication in the world of hardware development.

The RP2350's Future Remains Uncertain

For now, the future of the RP2350 remains uncertain. Will Raspberry Pi be able to address this flaw with a new chip revision, or will developers need to find long-term workarounds? Only time will tell, but one thing is clear: the road from the RP2040 to its successor has proven to be more challenging than anyone anticipated.

Source:  hackster.io - Problems with the Raspberry Pi Pico 2, Raspberry Pi RP2350 Deepen as Projects Hit By Erratum E9

Images:  Raspberry Pi