5. Pin Function and Description
USB (S2R72A42)
Pin No.
18
Name
I/O
−
RESET
Description
NC
NC
NC
NC
NC
NC
NC
NC
−
−
−
−
−
−
−
−
Not used (leave open)
Not used (leave open)
Not used (leave open)
Not used (leave open)
Not used (leave open)
Not used (leave open)
Not used (leave open)
Not used (leave open)
17
−
21
−
20
−
27
−
34
−
28
−
35
−
POWER (applies to S2R72A44/A43/A42)
Pin No.
Name
HVDD
Voltage
3.3 V
1.8
Description
4, 9, 15, 31, 42
3.3 V supply for USB and IO
1.8 V supply for internal core
GND
3, 8, 16, 29, 43, 46
6, 11, 19, 30, 40, 48
LVDD
VSS
0 V
5.1 VBUS switch management
Dx{x=1-4}_VBUSEN pins corresponding to each down ports are surved for this purpose.
VBUS switch devices connected to those pins can be managed individually (Individual mode, i.e. MODE2 =
High) or concurrently (Gang mode, i.e. MODE2 = Low).
Assertion of VBUSEN signals are caused only by SetPortFeature(PORT_POWER) standard request which is
issued by the Host. Further conditions as listed below are required for VBUSEN signals to be asserted at that
moment.
- MODE1 pin is set to High (i.e. bPwrOn2PwrGood = 0b1)
- The LSI is under configured condition (as USB standard meaning) as a result of receiving SetConfiguration()
standard request from the Host.
- Dx{x=1-4}_VBUSFLG pins correspoinding to each of down ports are not forced to low.
If each of those VBUSFLG signals is asserted, PORT_OVER_CURRENT status on each down port is set.
Those statuses can be checked with GetPortStatus() standard request which is issued repeatedly by ordinaly host
stacks.
Lack of at least one of above conditions causes nagation of VBUSEN signal. Once VBUSEN is negated, it is not
asserted again without reception of SetPortFeature(PORT_POWER) even if conditions are returned in order.
In Gang mode, D1_VBUSEN alone is served for the VBUS management function.
Please refer to the USB 2.0 standard for USB defined things such as bPwrOn2PwrGood condition, standard
requests, Individual mode or Gang mode.
S2R72A4x Series Data Sheet
(Rev.1.20)
Seiko Epson Corporation
9
EPSON [ EPSON COMPANY ]
