COM20051I Datasheet, PDF (31/74 Pages) SMSC Corporation – Integrated Microcontroller and ARCNET (ANSI 878.1) Interface

BIT BIT NAME
7 Read Data
6 Auto Increment
Table 10 - Address Pointer High Register
SYMBOL
DESCRIPTION
RDDATA
This bit tells the ARCNET core whether the following
access will be a read or write. A logic "1" prepares the
device for a read, a logic "0" prepares it for a write.
AUTOINC
This bit controls whether the address pointer will
increment automatically. A logic "1" on this bit allows
automatic increment of the pointer after each access,
while a logic "0" disables this function. Please refer to
the Sequential Access Memory section for further detail.
5-2 (reserved)
1-0 Address 9-8
A9-A8
These bits are undefined.
These bits hold the upper two address bits which provide
addresses to RAM.
BIT BIT NAME
7-0 Address 7-0
Table 11 - Address Pointer Low Register
SYMBOL
DESCRIPTION
A7-A0
These bits hold the lower 8 address bits which provide
the addresses to RAM.
BIT BIT NAME
Table 12 - Configuration Register
SYMBOL
DESCRIPTION
7 Reset
RESET
6 Command CCHEN
Chaining
Enable
5 Transmit
Enable
TXEN
A software reset of the ARCNET core is executed by
writing a logic "1" to this bit. A software reset does not
reset the microcontroller interface mode, nor does it
affect the Configuration Register. The only registers that
the software reset affect are the Status Register, the
Next ID Register, and the Diagnostic Status Register.
This bit must be brought back to logic "0" to release the
reset. The Software Reset applies only to the ARCNET
core. It does not apply to the 8051 microcontroller of the
COM20051I.
This bit, if high, enables the Command Chaining
operation of the device. Please refer to the Command
Chaining section for further details. A low level on this
bit ensures software compatibility with previous SMSC
ARCNET devices.
When low, this bit disables transmissions by keeping
nPULSE1, nPULSE2 if in non-Backplane Mode, and
nTXENABLE inactive. When high, it enables the above
signals to be activated during transmissions. This bit
defaults low upon reset. This bit is typically enabled
once the Node ID is determined, and never disabled
during normal operation. Please refer to the Improved
Diagnostics section for details on evaluating network
activity.
SMSC DS – COM20051I
Page 31
Rev. 03/27/2000