MC9328MXL Datasheet, PDF (66/84 Pages) Freescale Semiconductor, Inc – i.MX Integrated Portable System Processor

Specifications
3.16 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)
USBD_VPO
(Output)
1 ^t ROE_VPO
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 52. USB Device Timing Diagram for Data Transfer to USB Transceiver (TX)
Table 26. USB Device Timing Parameter Table for Data Transfer to USB Transceiver (TX)
Ref No.
Parameter
1.8V ± 0.10V
3.0V ± 0.30V
Unit
Minimum Maximum Minimum Maximum
1
t_{ROE_VPO}; USBD_ROE active to
USBD_VPO low
2
t_{ROE_VMO}; USBD_ROE active to
USBD_VMO high
3
t_{VPO_ROE}; USBD_VPO high to
USBD_ROE deactivated
83.14
81.55
83.54
83.47
81.98
83.80
83.14
81.55
83.54
83.47
ns
81.98
ns
83.80
ns
MC9328MXL Advance Information, Rev. 5
66
Freescale Semiconductor