
i.MX25 Applications Processor for Consumer and Industrial Products, Rev. 9
Freescale Semiconductor 117
3.7.20 USBOTG Timing
This section describes timing for the USB OTG port and host ports. Both serial and parallel interfaces are
described.
3.7.20.1 USB Serial Interface Timing
The USB serial transceiver is configurable to four modes supporting four different serial interfaces:
• DAT_SE0 bidirectional, 3-wire mode
• DAT_SE0 unidirectional, 6-wire mode
• VP_VM bidirectional, 4-wire mode
• VP_VM unidirectional, 6-wire mode
The following subsections describe the timings for these four modes.
3.7.20.1.1 DAT_SE0 Bidirectional Mode Timing
Table 90 defines the DAT_SE0 bidirectional mode signals.
Figure 89 shows the USB transmit waveform in DAT_SE0 bidirectional mode diagram.
Figure 89. USB Transmit Waveform in DAT_SE0 Bidirectional Mode
2
F
baud_rate
: Baud rate frequency. The maximum baud rate the UART can support is (
ipg_perclk
frequency)/16.
Table 90. Signal Definitions—DAT_SE0 Bidirectional Mode
Name Direction Signal Description
USB_TXOE_B Out Transmit enable, active low
USB_DAT_VP Out
In
Tx data when USB_TXOE_B is low
Differential Rx data when USB_TXOE_B is high
USB_SE0_VM Out
In
SE0 drive when USB_TXOE_B is low
SE0 Rx indicator when USB_TXOE_B is high
USB_DAT_VP
USB_SE0_VM
US1
US2
Transmit
US4
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