Owner's manual

12 ©Copyright 2005 Cirrus Logic, Inc. DS651UM23
Version 2.3
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.
The host port can operate in two modes in order to accomodate Motorola
®
or Intel
®
style
interfaces. The default mode is Motorola. Intel mode is set via a firmware modification.
4.2.2 Asynchronous Serial Port (UART Bridge) Signals
Level-shifting drive circuits are typically required between these signals and any external
connections.
Table 2-1: Host Port Signals
Signal Description Direction
CM-2
Pin #
CS1810xx/
CS4961xx 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 (Motorola mode).
HRD Host Read In J1:A4 107 Host Read (Intel mode).
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 (Motorola mode).
HWR
Host Write In J1:A5 103 Host Write (Intel mode).
HEN
Host Enable In J1:A7 104 Host Port Enable.
HCS
Select In J1:A7 104 Select (Intel mode).
Signal Description Direction
CM-2
Pin #
CS1810xx/
CS4961xx 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.