MC9328MX1 Datasheet, PDF (80/96 Pages) Freescale Semiconductor, Inc – i.MX Integrated Portable System Processor

Specifications
3.19 USB Device Port
Four types of data transfer modes exist for the USB module: control transfers, bulk transfers, isochronous transfers,
and interrupt transfers. From the perspective of the USB module, the interrupt transfer type is identical to the bulk
data transfer mode, and no additional hardware is supplied to support it. This section covers the transfer modes and
how they work from the ground up.
Data moves across the USB in packets. Groups of packets are combined to form data transfers. The same packet
transfer mechanism applies to bulk, interrupt, and control transfers. Isochronous data is also moved in the form of
packets, however, because isochronous pipes are given a fixed portion of the USB bandwidth at all times, there is
no end-of-transfer.
USBD_AFE
(Output)
USBD_ROE
(Output)
1 ^t ROE_VPO
USBD_VPO
(Output)
6
t_PERIOD
t _{VMO_ROE} 4
3
t_{VPO_ROE}
USBD_VMO
(Output)
USBD_SUSPND
(Output)
t_{ROE_VMO}
2
t_{FEOPT 5}
USBD_RCV
(Input)
USBD_VP
(Input)
USBD_VM
(Input)
Figure 61. USB Device Timing Diagram for Data Transfer to USB Transceiver (TX)
Table 37. USB Device Timing Parameter Table for Data Transfer to USB Transceiver (TX)
Ref No.
Parameter
Minimum Maximum Unit
1
t_{ROE_VPO}; USBD_ROE active to USBD_VPO low
83.14
83.47
ns
2
t_{ROE_VMO}; USBD_ROE active to USBD_VMO high
81.55
81.98
ns
3
t_{VPO_ROE}; USBD_VPO high to USBD_ROE deactivated
83.54
83.80
ns
4
t_{VMO_ROE}; USBD_VMO low to USBD_ROE deactivated (includes SE0) 248.90
249.13
ns
5
t_FEOPT; SE0 interval of EOP
160.00
175.00
ns
MC9328MX1 Advance Information, Rev. 4
80
Freescale Semiconductor