Motorola MVME166IG/D2 - Manual (Page 31)

Functional Description
MVME166IG/D2 1-17
1
Programmable Tick Timers
Four 32-bit programmable tick timers with 1
µ
s resolution are provided, two
in the VMEchip2 and two in the PCCchip2. The tick timers can be
programmed to generate periodic interrupts to the processor.
Watchdog Timer
A watchdog timer function is provided in the VMEchip2. When the watchdog
timer is enabled, it must be reset by software within the programmed time or
it times out. The watchdog timer can be programmed to generate a SYSRESET
signal, local reset signal, or board fail signal if it times out.
Software-Programmable Hardware Interrupts
Eight software-programmable hardware interrupts are provided by the
VMEchip2. These interrupts allow software to create a hardware interrupt.
Local Bus Timeout
The MVME166 provides a timeout function 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 selectable by
software for 8
µ
sec, 64
µ
sec, 256
µ
sec, or infinite. The local bus timer does not
operate during VMEbus or VSB bound cycles. VMEbus bound cycles are
timed by the VMEbus access timer and the VMEbus global timer. VSB bound
cycles are timed by the VSB access timer, the VSB transfer timer, and if its serial
arbiter is enabled, by the VSB arbitration timer.
Connectors
The MVME166 has two 96-position DIN connectors: P1 and P2. P1 rows A, B,
C, and P2 row B provide the VMEbus interconnection. P2 rows A and C, on
the MVME166, provide the connection to the VSB. The MVME166 has a 20-pin
connector mounted behind the front panel. When the MVME166 board is
enclosed in a chassis and the front panel is not visible, this connector allows
the reset, abort and LED functions to be extended to the control panel of the
system, where they are visible. The MVME166 has a 68-pin mini D ribbon
shielded connector for the SCSI bus interface. The MVME166 has a 100-pin
mini D ribbon shielded connector for the serial ports, Ethernet, and printer.