Card Reader Firmware Updates via Audio Plug
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Solution Overview
Problem
Conventional card reader devices are limited to unidirectional communication, making it impossible to update their firmware without disassembly, leading to users operating with outdated software or firmware versions, which can result in errors during payment processes and a lack of access to new features.
Innovation Solution
A bidirectional communication system using a standard 3.5 mm audio plug allows incremental firmware updates to be transferred to the card reader device without user intervention, utilizing both audio channels for data exchange and storing multiple firmware versions to ensure continuous functionality and error handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If unidirectional communication is used in card reader devices, then device simplicity is maintained, but firmware update capability is lost
Solution Approach 1:
The audio plug interface is made multi-functional by enabling it to handle both audio signal transmission and firmware data transfer. The system uses the existing audio channels bidirectionally, allowing the same physical interface to serve multiple purposes: normal audio communication and firmware updates, thereby adding adaptability without requiring additional dedicated update ports
2Ease of manufacture
If firmware updates require device disassembly, then device security is maintained, but ease of maintenance deteriorates
Solution Approach 1:
The system performs preliminary actions by downloading and storing firmware updates in advance in a secondary memory area while the device continues to operate with the current firmware. The boot loader is pre-configured to detect and load new firmware automatically, eliminating the need for disassembly and ensuring continuous operational reliability
3Loss of time
If incremental firmware updates are implemented, then update time is reduced, but risk of update interruption increases
Solution Approach 1:
The system provides beforehand cushioning by maintaining two separate firmware areas (first and second areas) in memory. If an incremental update is interrupted or fails, the boot loader can automatically switch to the previous working firmware area, ensuring device reliability. This redundant storage structure acts as a safety buffer against update failures
4Adaptability or versatility
If bidirectional communication is enabled through audio plug, then firmware update capability is achieved, but communication protocol complexity increases
Solution Approach 1:
The system introduces an intermediary layer in the form of a specially designed boot loader that mediates between the audio plug interface and the firmware update process. The boot loader handles the complex bidirectional communication protocols, data validation, and memory management, shielding the main device logic from protocol complexity while enabling sophisticated firmware update capabilities
Data Source
AI summary
Aspects of the subject disclosure provide a card reader for receiving payment card information at a mobile point-of-sale terminal. In some implementations, a reader of the subject technology can include a memory, a conditioning module and a 3.5 mm audio plug including an audio bus that is configured for insertion into a headphone port of a host device, such as a smart phone or tablet computer. Implementations of the subject technology also include a microprocessor configured to perform operations for determining whether a newer firmware version is available for the card reader or whether a download of such a firmware needs to be completed, and in response to determining such a download is needed, performing a download of the firmware via the audio plug during periods of inactivity.