USB Programming ICs vs GWU2X and GWU2U

By Grant Jennings, Sr. Director of International Marketing, GOWIN Semiconductor Corp.

The GOWIN GWU2X and GWU2U peripheral bridging ICs provide conversation from USB to JTAG, SPI, I2C, UART and GPIOs.  This conversion is often required when programming and communicating with other IC’s on development and production circuit boards.  Most host computers include a USB port, but do not have the chip to chip peripherals typically used for programming.

              There are several types of USB to peripheral bridging devices IC.  So, what makes the GOWIN GWU2U and GWU2X different?  The first notable difference is in the architecture.  Most existing USB to peripheral bridges use a combination of a CPU, hardened IPs and also emulated interfaces through GPIOs and a software API.  The GWU2X and GWU2U instead uses a programmable gate architecture with a direct conversion path from USB to the interface.  The interface is directly driven by the hardware.  This provides lower latency and less interoperability issues since the data path does not have to flow through both hardware and software paths.  In some cases it also provides superior reliability on the peripheral side for alternatives that rely on bit-bashing GPIO to emulate the interface. 

              Using a dedicated hardware bridging solution provides many benefits. First, if you’ve used CPU based bridging devices in the past you’ve probably experienced issues with drivers.  This is often related to use of non-generic, proprietary USB drivers that are required to use the bridging device.  The GOWIN GWU2 series by comparison use LibUSB, WinUSB and VCP (Virtual COM Port) drivers, which are native to most computer operating systems.  When using proprietary drivers, users are relying on the chip manufacturer to provide fully tested drivers and correlating CPU IC firmware to ensure reliable behavior across a vast range of hardware platforms.

The second benefit of a dedicated hardware implementation is cost. Using a processor and memory to bridge between USB and the peripheral interface is not only more complex, but consumes additional chip area and costs more as a result.

The third benefit is product life cycle.  GOWIN is a programmable semiconductor IC company and aligns it’s products to various semiconductor fabrication process nodes.  Most of the USB to peripheral interface bridges to date are on much older process nodes, resulting in a larger die size and increased per-device cost.  To move these devices to a new process node would involve considerable engineering efforts, because the chip design needs to be reverified, interface IPs would need to be relicensed for the new process node and firmware running on the CPU would need to be reverified.  GOWIN’s GWU2X and GWU2U architecture does not have these burdens.  It is a pure digital logic design and the interfaces have been developed and validated by GOWIN themselves.  This means the design is easily portable through various generations and process nodes, CPU firmware does not need to be reverified, interfaces do not need to be redesigned and IP licenses do not need to be renegotiated.

Devices with fixed ASIC IP often have issues supporting variances and nuances related to the interpretation peripheral specification it’s attempting to support.  Sometimes these issues can be resolved by placing capacitors on certain interface IO to delay the signaling appropriately.  In other cases, the interface bridge simply cannot support communication with the desired IC.  Both of these cause major impacts to engineering development.  The GOWIN GWU2X and GWU2U have programmable RTL based interface firmware is continually being updated to compensate for various interface nuances over time rather than a fixed interface IP that would require a chip redesigned in order to fix the issue.

Another notable difference relates to supported IO voltage range and capability.  Since many of the peripheral bridges on the market today are on older process nodes it’s common that they only support limited voltage range.  Also, many times the IO will be fixed in a particular direction by the firmware.  This causes product developers to often add voltage translators or IO gating capabilities if other IO voltage ranges or programming paths are required.  The GWU2X can drive a wider voltage range and supports placing the IO in a high impedance state when not in use.

Total BOM cost is another concern.  Some interface bridging IC’s require two voltages, external rom and various passives.  The GWU2X and GWU2U can be powered by a single supply, does not need external memory, can operate on a low cost crystal oscillator, and only need decoupling capacitors for passives.  This along with the supported IO voltage capabilities can lower the BOM requirements over other bridge ICs.  Additionally, The GWU2U can be combined with other GOWIN devices, FPGAs, and IPs such as USB Type-C PD (Power Delivery) to enhance the traditional interface bridge with additional capabilities

In conclusion, GOWIN’s GWU2X and GWU2U USB to peripheral interface bridge ICs provide several benefits overcoming difficulty of development, cost, and product lifetime burdens of the legacy ICs in the market before it.

To learn more about GOWIN’s GWU2X and GWU2U Bridging IC’s, please visit us the ASSP device product pages here - https://www.gowinsemi.com/en/product/detail/25/