User manual

Page 15
Document No. 80-15151 Issue 6 HEBER LTD
5.12 DIL Switches
The Pluto 5 board is equipped with two 8 way DIL Switches, SW1 and SW2. These are read at the
same addresses as the 32 Inputs (see preceding Section).
Table 12. Mapping of DIL Switch Inputs
D15-D12 D11 D10 D9 D8 D7-D0
Base+6
0xF
SW2:8 SW2:7 SW1:8 SW1:7 IP31-24
Base+4
0xF
SW2:6 SW2:5 SW1:6 SW1:5 IP23-16
Base+2
0xF
SW2:4 SW2:3 SW1:4 SW1:3 IP15-8
Base
0xF
SW2:2 SW2:1 SW1:2 SW1:1 IP7-0
5.13 Software Controlled Indicator LED
LD2 is a green LED that may be turned on or off under software control (see Schematic Sheet 9 - IO
Connectors). The LED may be used to provide an indication that software is running or perhaps for
fault diagnosis.
The PORTA2 line from the MC68340 SIM40 Module drives the LED. After reset, the PORTA pins are
high impedance and pulled high by resistor network N11. This signal passes through the inverter U7F
which thus turns ON the LED. Therefore, initially and with no action on the part of the software, the
LED will be ON indicating that Vcc is present.
If the software sets PORTA2 pin as an output and drives it low, the LED will go OFF.
The PORTA pins are taken to the I/O Expansion Connector P14. Future I/O Expansion Cards may use
the PORTA2 pin for some other function, in which case this will have to be taken into consideration
when operating the indicator LED.
5.14 On-board Push Button
A Push Button Switch, SW3, is provided on the board (see Schematic Sheet 2 - CPU). The function of
this switch is at the discretion of the user of the board.
It is connected so as to pull the PORTA3 line from the MC68340 SIM40 Module to Gnd when
operated.
The PORTA pins are taken to the I/O Expansion Connector P14. Future I/O Expansion Cards may use
the PORTA3 pin for some other function, in which case the possible interaction with SW3 will have to
be taken into account.
5.15 Multiplexer
The Pluto 5 Controller board provides hardware assistance (within the FPGA) to the Processor
allowing two 32*16 Multiplex Arrays (referred to below as MPX1 and MPX2) to be controlled. From a
“logical” or software point of view, these arrays are uncommitted and may be configured to be either
Lamp or LED drives, depending on what interface components are fitted. When running the lamps
from a 48V supply, a 1 in 16 duty cycle is employed on the column strobes (sinks) allowing the full
capabilities of the two arrays, MPX1 and MPX2 to be utilised. If the multiplexed lamps are run from a
36V supply, a 1 in 8 duty cycle must be utilised and the useable size of the two arrays reduces to
32*8.
The Pluto 5 256/32 Controller Board is intended for customers who run with a 48V lamp supply and
require the maximum drive capability of the board. It has ½ of MPX1 configured as a 16*16 (256)
Lamp Drive Array and the other ½ configured as a 16*16 (32 seven-segment digits) LED Drive Array.