28 USB FUNCTION CONTROLLER (USB)
S1C33L26 TECHNICAL MANUAL
Seiko Epson Corporation
28-15
(1) When the cable is connected, VBUS turns to HIGH and the macro sets the USB_Status.VBUS and
SIE_IntStat.VBUS_Changed bits (T
0
).
(2) If the SIE_IntEnb.EnVBUS_Changed and MainIntEnb.EnSIE_IntStat bits are set, the macro asserts the
#INT signal.
(3) Set USBCLK_EN to start supplying the USB clock (T
1
).
(4) Clear USBSNZ (T
2
).
(5) The downstream port sends out Reset (T
4
).
USBCLK_EN
USBSNZ
ActiveUSB
DisBusDetect
OpMode[1:0]
LineState[1:0]
USBDP/USBDM
Internal clock
time
(VBUS)
Upstream
Port Actions
Device
Actions
T
0
T
4
T
1
T
2
T
3
"0x0" (Normal Mode)
Fully meet USB2.0 required frequency
"J" State
FS Idle ("J" State)
SE1
SE0
SE0
SE0
CLK
Powerup time
5.1.11 Device Attach Timing
Figure 28.
5.1.5 Device Attach Timing Values
Table 28.
Timing parameter
Description
Value
T0
VBUS is enabled.
0 (Reference)
T1
Set USBCLK_EN to 1 (on the firmware).
The clock input starts.
T
1
T2
Clear USBSNZ to 0 (on the firmware).
T
1
+ 250 ms < T
2
T3
Set ActiveUSB to 1.
Set OpMode[1:0] to 0x0 (on the firmware).
T
0
+ 100 ms < T
3
T4
The downstream port sends out Reset.
Set DisBusDetect to 1 (on the firmware).
T
3
+ 100 ms < T
4