MC2 Chip

3

Access and Watchdog Time Base Select Register

The watchdog timer control logic in the MC2 chip is used with the "No VMEbus Interface" option. This function is duplicated at the same bit locations in the VMEchip2 at location $FFF4004C. It is permissible to enable the watchdog timer in both the VMEchip2 and the MC2 chip.

ADR/SIZ

 

 

 

 

$FFF42044 (8 bits)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

BIT

15

 

14

13

 

12

11

 

10

 

9

8

 

 

 

 

 

 

 

 

 

 

 

 

 

NAME

 

 

 

 

LBTO

 

 

 

WDTO

 

 

 

 

 

 

 

 

 

 

 

OPER

R/W

 

 

R/W

 

 

 

R/W

 

 

 

 

 

 

 

 

 

 

 

RESET

0

 

 

0PL

 

 

 

0 PL

 

 

 

 

 

 

 

 

 

 

 

 

 

 

WDTO These bits define the watchdog time-out period:

Bit

Time-out

Encoding

 

 

 

0

512 μs

 

 

1

1 ms

 

 

2

2 ms

 

 

3

4 ms

 

 

4

8 ms

 

 

5

6 ms

 

 

6

32 ms

 

 

7

64 ms

 

 

Bit

Time-out

Encoding

 

 

 

8

128 ms

 

 

9

256 ms

 

 

10

512 ms

 

 

11

1 s

 

 

12

4 s

 

 

13

16 s

 

 

14

32 s

 

 

15

64 s

 

 

LBTO These bits define the local bus time-out value. The timer begins timing when TS is asserted on the local bus. If TA or TEA is not asserted before the timer times out, a TEA

3-44

Computer Group Literature Center Web Site

Page 232
Image 232
Motorola MVME172 manual Access and Watchdog Time Base Select Register, Wdto These bits define the watchdog time-out period