Motorola MVME166IG/D2 manual MC68230 Parallel Interface/Timer

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Board Level Hardware Description

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.

1-14 MVME166 Single Board Computer Installation Guide