UM10360 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved.
User manual Rev. 3 — 19 December 2013 204 of 841
NXP Semiconductors
UM10360
Chapter 10: LPC176x/5x Ethernet
After a reset, the state machine is in the INACTIVE state. As soon as the RxEnable bit is
set in the Command register, the state machine transitions to the ACTIVE state. As soon
as the RxEnable bit is cleared, the state machine returns to the INACTIVE state. If the
receive data path is busy receiving a packet while the receive data path gets disabled, the
packet will be received completely, stored to memory along with its status before returning
to the INACTIVE state. Also if the Receive descriptor array is full, the state machine will
return to the INACTIVE state.
For the state machine in Figure 25
, a soft reset is like a hardware reset assertion, i.e. after
a soft reset the receive data path is inactive until the data path is re-enabled.
Enabling and disabling transmission
After reset, the transmit function of the Ethernet block is disabled. The Tx transmit data
path can be enabled by the device driver setting the TxEnable bit in the Command
register to 1.
The status of the transmit data paths can be monitored by the device driver reading the
TxStatus bit of the Status register. Figure 26
illustrates the state machine for the
generation of the TxStatus bit.
Fig 25. Receive Active/Inactive state machine
ACTIVE
RxStatus = 1
INACTIVE
RxStatus = 0
RxEnable = 1
RxEnable = 0 and not busy receiving
OR
RxProduceIndex = RxConsumeIndex - 1
reset
xxxxxxxxxxxxxxxxxx
To Next Page
Loading...
Need help?
General
