FUSB302B
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7
Table 4. PROCESSOR CONFIGURES THE
FUSB302B THROUGH I
2
C
I
2
C Registers/Bits Value
TOGGLE 1
PWR 07H
HOST_CUR0 1
HOST_CUR1 0
MEAS_VBUS 0
VCONN_CC1 0
VCONN_CC2 0
Mask Register 0xFE
Maska Register 0xBF
Maskb Register
(Except I_TOGDONE and I_BC_LVL Interrupt)
0x01
PWR[3:0] 0xBF
1. Once it has been determined what the role is of the FUSB302B,
it returns I_TOGDONE and TOGSS1/2.
2. Processor then can perform a final manual check through I
2
C.
Manual Device Toggle
The FUSB302B has the capability to do manual DRP
toggle. In manual toggle the FUSB302B is configurable by
the processor software by I
2
C and setting TOGGLE = 0.
Manual Device Detection and Configuration
A Type-C device must monitor VBUS to determine if it is
attached or detached. The FUSB302B provides this
information through the VBUSOK interrupt. After the
Type-C device knows that a Type-C host has been attached,
it needs to determine what type of termination is applied to
each CC pin. The software determines if an Ra or Rd
termination is present based on the BC_LVL and COMP
interrupt and status bits.
Additionally, for Rd terminations, the software can
further determine what charging current is allowed by the
Type-C host by reading the BC_LVL status bits. This is
summarized in Table 5.
Toggle Functionality
When TOGGLE bit (Control2 register) is set the
FUSB302B implements a fixed DRP toggle between
presenting as a SRC and as a SNK. It can also be configured
to present as a SRC only or SNK only and poll CC1 and CC2
continuously. This operation is turned on with TOGGLE = 1
and the processor should initially write HOST_CUR1 = 0,
HOST_CUR0 = 1 (for default current), VCONN_CC1 =
VCONN_CC2 = 0, Mask Register = 0xFE, Maska
register = 0xBF, and Maskb register = 0x01, and PWR =
0x01. The processor should also read the interrupt register
to clear them prior to setting the TOGGLE bit.
Table 5. DEVICE INTERRUPT SUMMARY
Status Type
Interrupt Status
Meaning
BC_LVL[1:0] COMP COMP Setting VBUSOK
CC Detection
2’b00 NA NA 1 vRA
2’b01 NA NA 1 vRd−Connect and vRd−USB
2’b10 NA NA 1 vRd−Connect and vRd−1.5
2’b11 0 6’b11_0100
(2.05 V)
1 vRd−Connect and vRd−3.0
Attach NA NA NA 1 Host Attached, VBUS Valid
Detach NA NA NA 0 Host Detached, VBUS Invalid
The high level software flow diagram for a Type-C device
(SNK) is shown in Figure 7.
