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If the endpoint is used in single buffer mode, program the following:
• Set STALL bit (S) to zero
• Set toggle reset bit (TR) to one and set toggle value bit (TV) to zero
If the endpoint is used in double buffer mode, program the following:
• Set the STALL bit of buffer 0 and buffer 1 to 0.
• Read the buffer in use bit for this endpoint
• Set the toggle reset bit (TR) to 1 and set the toggle value bit (TV) to 0 for the buffer
15.3.4.4 Set configuration
When a set configuration request is received with a configuration value different from
zero, the device firmware must enable all endpoints that will be used in this configuration
and reset all the toggle values. To do so, it must generate the procedure explained in
clear feature (endpoint HALT) for every endpoint that will be used in this configuration.
For all endpoints that are not used in this configuration, it must set the disabled bit (D) to
one.
15.3.4.5 Suspend and resume
The USB suspend mode has been introduced in
power management by the USB device. This becomes even more important if the device
draws power from the bus (bus-powered device). The following constraints should be
met by the bus-powered device:
• A device in the non-configured state should draw only a maximum of 100mA from the
• A configured device can draw only up to what is specified in the Max Power field of
• A suspended device should draw only a maximum of 500 uA.
A device will go into the suspend mode if there is no activity on the USB bus for more
than 3 ms. A suspended device wakes up, if there is transmission from the host (host-
initiated wake up). The USB interface also supports software initiated remote wake up.
To initiate this, software on the device must enable all clocks and clear the suspend bit.
This will cause the hardware to generate a remote wake up signal upstream.
The assertion of the output signal indicates that there was no activity on the USB bus for
the last 3 ms. At this time an interrupt is sent to the processor on which the software can
start preparing the device for suspend.
If there is no activity for the next 2 ms, the signal indicating need for the clock will go low.
This means that the main clock can be switched off. When activity is detected on the
USB bus, USB suspend is deactivated and the signal indicating signal indicating need for
the clock is activated.
UM10858
User manual
COMPANY PUBLIC
indicated by the buffer in use bit.
USB bus.
the configuration descriptor. The maximum value is 500 mA
All information provided in this document is subject to legal disclaimers.
Rev. 1.4 — 14 May 2018
Section
314514
UM10858
PN7462 family HW user manual
8.2. The USB protocol enforces
© NXP B.V. 2018. All rights reserved.
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