MC94MX21DVKN3 Freescale, MC94MX21DVKN3 Datasheet - Page 60

• Manufacturer Part Number: MC94MX21DVKN3
• Manufacturer: Freescale

Specifications of MC94MX21DVKN3

• Operating Temperature (max): 70C
• Operating Temperature Classification: Commercial
• Mounting: Surface Mount
• Lead Free Status / RoHS Status: Compliant

Specifications
3.18
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, but because isochronous pipes are given a fixed portion of the USB bandwidth at
all times, there is no end-of-transfer.
60
Ref
No.
1
2
3
4
5
6
t
t
t
t
t
t
OEB
OEB
TXDP_
TXDM_
FEOPT
PERIOD
USB On-The-Go
_TXDP
_TXDM
USB_TXDM
USB_TXDP
OEB
; SE0 interval of EOP
OEB
; Data transfer rate
USB_ON
USB_VM
USB_OE
USB_VP
(Output)
(Output)
(Output)
(Output)
; USBD_OE active to USBD_TXDP low
; USBD_TXDP high to USBD_OE deactivated
Table 39. USB Timing Parameters for Data Transfer to USB Transceiver (TX)
; USBD_OE active to USBD_TXDM high
; USBD_TXDM low to USBD_OE deactivated (includes SE0)
Figure 50. USB Timing Diagram for Data Transfer to USB Transceiver (TX)
(Input)
(Input)
1
t
t
OEB_TXDM
OEB_TXDP
Parameter
2
MC94MX21 Technical Data, Rev. 1.
t
PERIOD
6
t
t
FEOPT
TXDM_OEB
Minimum
83.14
81.55
83.54
248.9
11.97
160
5
3.0 V ± 0.3 V
4
Freescale Semiconductor
t
TXDP_OEB
Maximum
3
249.13
83.47
81.98
12.03
83.8
175
Mb/s
Unit
ns
ns
ns
ns
ns