Motorola MVME166IG/D2 - Manual (Page 28)

Board Level Hardware Description
1-14 MVME166 Single Board Computer Installation Guide
1
at synchronous bit rates up to 64 k bits per second. They use RXD, CTS, DCD,
TXD, RTS, DTR, and DSR. They also interface to the synchronous clock signal
lines. Additional control signals are provided for each serial port by the
MC68230. These include local loopback control, self test control, and ring
indicator. The ring indicator signal can be programmed to generate a local bus
interrupt. Refer to the MC68230 section for additional information. Note that
the usable functionality of the serial ports depends on the transition module
used.
All four serial ports on the MVME166 use a TTL interface to the transition
board. This allows the interface specific drivers to be located on the transition
board. This allows more flexibility in configuring the serial ports for different
interfaces like EIA-232-D or V.35. An external I/O transition module such as
the MVME712-10 should be used to provide configuration headers, interface
drivers, and industry-standard connectors.
The interface provided by the PCCchip2 allows the 16-bit CD2401 to appear at
contiguous addresses; however, accesses to the CD2401 must be 8 or 16 bits.
32-bit accesses are not permitted. Refer to the CD2401 data sheet for detailed
programming information.
The CD2401 supports DMA operations to local memory. Because the CD2401
does not support a retry operation necessary to break VMEbus or VSB dual
port lockup conditions, the CD2401 DMA controllers should not be
programmed to access the VMEbus or VSB. The hardware does not restrict the
CD2401 to onboard DRAM.
MC68230 Parallel Interface/Timer
The MVME166 provides an MC68230 parallel interface/timer (PI/T) chip.
When the MVME166 is used with the MVME712-10 transition module or the
MVME712-06/07/09 I/O distribution board set, the MC68230 is used to
provide additional control lines for the serial ports. These include local
loopback, self test, and ring indicator. The ring indicator signals can be
programmed to generate local bus interrupts. Refer to the MVME712-10
transition module manual for more information.
The base address of the MC68230 is $FFF45E00, and because it is an 8-bit
device it appears only at odd addresses. Space for the MC68230 was created
by dividing the area occupied by redundant copies of the CD2401 registers
into eight segments. The CD2401 is still addressed at $FFF45000 to $FFF451FF.
Addresses $FFF45200 to $FFF45BFF are reserved, and if accessed on an
MVME166 cause a local bus timeout error, if the local bus timer is enabled.
The address range from $FFF45C00 to $FFF45DFF always returns a local bus
timeout error if the local bus timer is enabled. The CD2401 appears
redundantly from $FFF45200 to $FFF45FFF on the MVME167/187.