12
©
Copyright 2004 Cirrus Logic, Inc.
DS651UM21
Version 2.1
CobraNet Hardware User’s Manual
Pinout and Signal Descriptions
4.2
Signal Descriptions
4.2.1 Host Port Signals
The host port is used to manage and monitor the CobraNet interface. Electrical operation
and protocol is detailed in the
"Host Management Interface (HMI)" on page 23
of this
Manual.
4.2.2 Asynchronous Serial Port (UART Bridge) Signals
Level-shifting drive circuits are typically required between these signals and any external
connections.
Signal
Description
Direction
CM-2
Pin #
CS181xx
Pin #
Notes
HDATA[7:0] Host
Data
In/Out
J1:A19,
A[17:11]
111, 112,
114, 115,
117, 118,
102, 121
Host port data.
HADDR[3:0] Host
Address
In
J1:A20,
A[10:8]
105, 106,
109,110
Host port address.
HRW
Host
Direction
In
J1:A4
107
Host port transfer direction.
HREQ
Host Request
Out
J1:A6
140
Host port data request.
HACK
Host Alert
Out
J1:A3
102
Host port interrupt request.
HDS
Host Strobe
In
J1:A5
103
Host port strobe.
HEN
Host Enable
In
J1:A7
104
Host Port Enable.
Signal
Description
Direction
CM-2
Pin #
CS181xx
Pin #
Notes
UART_RXD
Asynchronous Serial
Receive Data
In
J1:A1
26
Pull-up to VCC if unused.
UART_TXD
Asynchronous Serial
Transmit Data
Out
J1:B1 25
UART_TX_OE
Transmit Drive Enable
Out
J1:A2
23
Enable transmit (active high) drive for two
wire multi-drop interface.