6.2.5 Channel Teardown
To perform a channel teardown, the host must do the following:
- When the host desires to tear down a channel (either RX or TX), it writes a 1 to the teardown field of the corresponding RX or TX Channel Global Configuration Register for that channel. The host should not disable the channel by writing a 0 to the enable field of this register. The PKTDMA will do this when finished with the teardown.
When the PKTDMA detects the teardown bit is set, it will:
TX Teardown |
|
RX Teardown |
- Allow the current packet to complete normally.
- Clear the channel enable bit in the TX Channel Global Configuration Register. The teardown bit will remain set as an indication that a teardown was performed.
|
|
- Signals the attached peripheral (rx_teardown_req) that a teardown was requested by the Host.
- Waits for the peripheral to acknowledge (rx_teardown_ack).
- Notes:
- During this time, processing continues normally.
- In some peripherals, rx_teardown_req and rx_teardown_ack are tied together in loopback.
- Following ack, the current packet is allowed to complete normally.
- Clear the channel enable in the RX Channel Global Configuration Register. The teardown bit will remain set as an indication that a teardown was performed.
|
The host detects the teardown is complete by examining the RX/TX Channel Global Configuration Register to check the enable status.