SLLSES1D December 2015 – September 2020 HD3SS3220
PRODUCTION DATA
The HD3SS3220 can be configured to operate as DRP when the PORT pin is left floating on the PCB. In DRP mode, the HD3SS3220 toggles between presenting as a DFP (Rp on both CC pins) and presenting as a UFP (Rd on both CC pins according to USB Type-C specification.
When presenting as a DFP, the HD3SS3220 monitors the voltage level on the CC pins looking for the R(d) termination of a UFP. When a UFP is detected and HD3SS3220 is in the attached. SRC state, the HD3SS3220 pulls the ID pin low to indicate to the system the port is attached to a sink (UFP). Additionally, when a UFP is detected, the HD3SS3220 supplies VCONN on the unconnected CC pin if Ra is also detected. In DFP mode, the HD3SS3220 will initially advertise default USB Type-C current. The Type-C current can be adjusted through I2C if the system wishes to increase the amount advertised. HD3SS3220 will adjust the R(p) resistors to match the desired Type-C current advertisement.
When presenting as a UFP, the HD3SS3220 monitors the CC pins for the voltage level corresponding to the Type-C current advertisement by the connected DFP. The HD3SS3220 will debounce the CC pins and wait for VBUS detection before successfully attaching. As a UFP, the HD3SS3220 detects and communicate the DFP advertised current level to the system through the OUT1 and OUT2 pins if in GPIO mode or through the I2C CURRENT_MODE_DETECT register once in the attached.SNK state.
The HD3SS3220 supports two optional Type-C DRP features called Try.SRC and Try.SNK. Products supporting dual-role functionality may have a requirement to be a source (DFP) or a sink (UFP) when connected to another dual-role capable product. For example, a dual-role capable notebook can be used as a source when connected to a tablet, or a cell phone could be a sink when connected to a notebook or tablet. When standard DRP products (products which don’t support either Try.SRC or Try.SNK) are connected together, the role (UFP or DFP) outcome is not predetermined. These two optional DRP features provide a means for dual-role capable products to connect to another dual-role capable product in the role desired. Try.SRC and Try.SNK are only available when HD3SS3220 is configured in I2C mode. When operating in GPIO mode, the HD3SS3220 will always operate as a standard DRP.
The Try.SRC feature of the HD3SS3220 device provides a means for a DRP product to connect as a DFP when connected to another DRP product that doesn’t implement Try.SRC. When two products which implement Try.SRC are connected together, the role outcome of either UFP or DFP is the same as a standard DRP. Try.SRC is enabled by changing I2C register SOURCE_PREF to 2’b11. Once the register is changed to 2’b11, the HD3SS3220 will always attempt to connect as a DFP when attached to another DRP capable device.