VMEBUS Interface
When the PME 68-1B is the current VMEbus master and the current access address is
higher than or equal to $100000 (an off-board address), a VMEbus transfer is initiated.
SYSCLK Signal
A Texas 74S241 driver is installed on PME 68-1B boards; this provides the 16 MHz,
SYSCLK VMEbus signal.
The SYSCLK driver can be isolated from the VMEbus via a jumper. Refer to Chapter 4
for further details.
SYSRESET* Signal
A jumper defines whether the board drives, receives or ignores the VMEbus signal
SYSRESET*. The RTC RESET is fixed to VME SYSRESET*. Refer to Chapter 4 for
further details.
RESET Switch
The RESET switch is a toggle switch located on the front panel (Figure 2). It can be
used to carry out a RESET of all devices on the PME 68-1B board: CPU, PIT, ACIA: or
produce a VME SYSRESET* signal. This carries out a general RESET of all boards
and devices within the system, including 68-1B RTC, and is the default condition.
SYSFAIL* Signal
The VMEbus specification defines a SYSFAIL* signal which informs all cards that one
(or more) card(s) in the system has failed. On PME 68-1B boards the user can enable or
disable the use of this signal. When enabled, an incoming SYSFAIL* will cause the CPU
to jump directly to the halt state and the HALT LED on the front panel to light. When
disabled the SYSFAIL* signal is ignored.
Address Modifier Codes
The VMEbus defines the address modifier signals. These in turn define the type of VME
access being executed.
PME68-1B Manual
Page 39 Issue 5
Содержание PME 68-1B
Страница 8: ...Figure 1 The PME 68 1B Board Photograph not available in PDF PME 68 1B Manual Page 2 Issue 5...
Страница 12: ...Figure 4 Component Layout Diagram P5 P4 P3 BAT PME 68 1B Manual Page 6 Issue 5...
Страница 56: ...Figure 14 Link Areas BAT PME68 1B Manual Page 50 Issue 5...
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Страница 59: ...Figure 15 Location of System EPROM Area 1 2 3 4 1 2 3 4 WC1 WC2 PME68 1B Manual Page 53 Issue 5...
Страница 80: ...Figure 41 Location of BERR Jumpers 1 2 3 4 WK1 WK2 BR26 2 3 1 BAT PME68 1B Manual Page 74 Issue 5...
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