Cirrus Logic EP93xx - Manual (Page 352)

9-50 DS785UM1
Copyright 2007 Cirrus Logic
1/10/100 Mbps Ethernet LAN Controller
EP93xx User’s Guide
9
9
9
Bit Descriptions:
GTC: General Timer Count, read only. The timer count contains
the running value of the timer function, it cannot be written
to directly. When the General Timer Period is written and
the same value is loaded into the General Timer Count, or
when the count value reaches 0, it is reloaded from the
General Timer Period. Additionally when the count
reaches zero, the Timeout Status (Interrupt Status register)
is set. The timer value is decremented at 1/8th of the
transmit bit rate.
GTP: General Timer Period, read/write. The Timer Period holds
the periodic time for the timer. When the period is written,
the count is preloaded with the same value. Setting a
value of zero in the Period disables the generation of
Timeout Status.
FCT
Address:
0x8001_0044 - Read/Write
Chip Reset:
0x0000_0000
Soft Reset:
0x0000_0000
Definition:
Flow Control Timer
Bit Descriptions:
RSVD: Reserved. Unknown During Read.
FCT: Flow Control Timer value. The Flow Control Timer is
loaded as a result of receiving a flow control frame, with
the pause value from the received frame. The value in the
timer is then decremented every 512 bit times, as soon as
the transmit line is idle. While the timer is non zero, no
new transmit frames are started. The decrement time
depends on the speed, but always corresponds to the
duration of a 64 byte minimum packet.
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
RSVD FCT
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
FCT