83C694 ETC, 83C694 Datasheet - Page 13

• Manufacturer Part Number: 83C694
• Description: TWISTED PAIR INTERFACE AND MACHESTER ENCODER/DECODER
• Manufacturer: ETC

83C694D
10
NUMBER
PIN
6
7
1
2
3
4
5
COL
NC
RXD
CRS
RES
RXC
SEL
MNEMONIC
Collision Detect
No Connect
Receive Data
Carrier Sense
Reset/Synch
Receive Clock
Mode Select
SIGNAL NAME
TABLE 3-1. PIN DESCRIPTION
O
I/O
O
O
O
I
I
I
A 10 MHz (+25%,-15%) signal at the CD
inputs (DTE mode) produces a logic high at
the COL output. When no signal is present at
the CD inputs, the COL output goes low. In
10BaseT operation, the COL output goes high
when TPR+ and TPR- are active while a
packet is being transmitted on TPX+/TPX-.
COL also goes high during SQE test or jabber
condition.
Do not connect any circuitry to this pin.
This is the NRZ data output from the on-chip
decoder and phase-locked loop. This signal
should be sampled by the controller at the
rising edge of receive clock. A high level is
binary "one", a low level is binary "zero".
CRS (DTE mode) goes high when valid data
is presen t at the RX+/RX- inp uts or
TPR+/TPR- inputs. It goes low after the last
bit is received at the inputs.
When RES is low, all internal nodes are set to
a known state except for internal clock distri-
bution. This improves testing procedures.
Normal operation is enabled on the rising
edge of RES and while RES is high. The RES
pin includes an internal pull up resistor, so it
may be left open if unused.
When the phase-locked loop acquires a valid
receive signal, a 10MHz clock signal (recov-
ered from receive data) is output on RXC.
RXC is low during idle (5 bit times after re-
ceive activity stops).
When SEL is high, TX+ and TX- outputs are
at the same voltage in idle state, providing a
"zero" differential. When SEL is low, TX+ is
positive with respect to TX- in idle state. Also,
three test modes may be selected by setting
the SEL pin to voltages between low and high
levels. Refer to section 2.13 for more on test
modes.
DESCRIPTION
PIN DESCRIPTION