Motorola 700/800-Series User Manual

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Board Level Hardware Description

Eight software-programmable hardware interrupts are provided 
by the VMEchip2. These interrupts allow software to create a 
hardware interrupt. Refer to the VMEchip2 description in the 
MVME162LX Embedded Controller ProgrammerÕs Reference Guide for 
detailed programming information. 

The MVME162LX provides a timeout function in the VMEchip2 
and the MC2chip for the local bus. When the timer is enabled and a 
local bus access times out, a Transfer Error Acknowledge (TEA) 
signal is sent to the local bus master. The timeout value is software-
selectable for 8 

µ

sec, 64 

µ

sec, 256 

µ

sec, or infinity. The local bus 

timer does not operate during VMEbus bound cycles. VMEbus 
bound cycles are timed by the VMEbus access timer and the 
VMEbus global timer. Refer to the VMEchip2 and the MC2chip 
descriptions in the MVME162LX Embedded Controller ProgrammerÕs 
Reference Guide for detailed programming information. 

The MC2chip also provides local bus timeout logic for 
MVME162LXs without the optional VMEbus interface (i.e., without 
the VMEchip2 ASIC).

The access timer logic is duplicated in the VMEchip2 and MC2chip 
ASICs. Because the local bus timer in the VMEchip2 can detect an 
offboard access and the MC2chip local bus timer cannot, the timer 
in the VMEchip2 is used in all cases except for the version of the 
MVME162LX which does not include the VMEbus interface 
(described under ÔÔNo-VMEbus-Interface optionÓ).