InterChip USB

{{Short description|Addendum to the USB-IF USB 2.0 specification}}

{{Confuse|Inter-Integrated Circuit{{!}}Inter-Integrated Circuit (I²C)}}

{{Use mdy dates|date=October 2021}}

InterChip USB (IC-USB), sometimes referred to as USB-IC or Inter-chip USB, is an addendum to the USB Implementers Forum (USB-IF) USB 2.0 specification. IC-USB is intended as a low-power variant of the standard physical USB interface, intended for direct chip-to-chip communications. The IC-USB bus's maximum length of 10 cm results in a lower inductance and capacitance and therefore allows lower power requirements. IC-USB is used primarily in embedded systems; for example, ETSI (in specification TS 102 600){{Cite web |url=https://www.etsi.org/deliver/etsi_ts/102600_102699/102600/10.01.00_60/ts_102600v100100p.pdf |title=ETSI TS 102 600 v10.1.0: Smart Cards; UICC-Terminal interface; Characteristics of the USB interface (Release 10) |date=September 2020 |accessdate=October 7, 2021 |website=ETSI |format=PDF}} has standardized on IC-USB as the official high-speed interface for connections between the main chipset of a smartphone and the SIM card or UICC card.

{{anchor|HSIC}}High-Speed Inter-Chip (HSIC) is a chip-to-chip variant of USB 2.0 that eliminates the conventional analog transceivers found in normal USB. It was adopted as a standard by the USB-IF in 2007. The HSIC physical layer uses about 50% less power and 75% less board area compared to traditional USB 2.0. HSIC uses two signals at 1.2 V and has a throughput of 480 Mbit/s. Maximum PCB trace length for HSIC is 10 cm. It does not have low enough latency to support RAM sharing between two chips.{{cite web |title= Interchip Connectivity: HSIC, UniPro, HSI, C2C, LLI... oh my! |url= http://info.arteris.com/blog/bid/59433/Interchip-Connectivity-HSIC-UniPro-HSI-C2C-LLI-oh-my |accessdate= June 24, 2011 |url-status= live |archiveurl= https://web.archive.org/web/20110619022557/http://info.arteris.com/blog/bid/59433/Interchip-Connectivity-HSIC-UniPro-HSI-C2C-LLI-oh-my |archivedate= June 19, 2011 }}{{cite web |title=USB High Speed Inter-Chip Interface |url=http://www.interfacebus.com/hsic-bus-high-speed-inter-chip-usb.html |accessdate= June 24, 2011 |url-status=live |archiveurl=https://web.archive.org/web/20110609163812/http://www.interfacebus.com/hsic-bus-high-speed-inter-chip-usb.html |archivedate=June 9, 2011}}

{{anchor|SSIC}}SuperSpeed Inter-Chip (SSIC) is the USB 3.0 successor of HSIC.{{cite web | url = https://www.synopsys.com/Company/Publications/DWTB/Pages/dwtb-transitioning-usb-jan2013.aspx | title = Transitioning from USB 2.0 HSIC to USB 3.0 SSIC | accessdate = August 7, 2015 | website = synopsys.com | url-status = dead | archiveurl = https://web.archive.org/web/20151007072152/http://www.synopsys.com/Company/Publications/DWTB/Pages/dwtb-transitioning-usb-jan2013.aspx | archivedate = October 7, 2015 }}

The USB-IF Inter-Chip USB Supplement was released in March 2006. ETSI TS 102 600, which is ETSI's USB implementation requirements specification, was first released in December 2007.