Micros Systems Workstation 4 LX Service Manual page 81

WS4 Technical Overview
Customer Display/Mag Card Reader Port (COM3)
The API switches the interface baud rate from 9600 to 115K baud. The Pole/Rear
LCD Customer Display interfaces are enabled by setting POLE_OE# low at
U47-4 to pass serial data appearing on to at U47-6.
MSR_POLE_TX TXD3 TXD3
drives a pair of OR gates in U11 that buffer the TX line to CN4-2 for the Pole
LCD Customer Display and J1-2 for the Rear LCD Customer Display.
The customer display interface can selectively receive serial data from the Rear or
Pole LCD Customer Display. One example of this is retrieving the firmware
version from the Rear or Pole LCD customer display.
To receive data from a Rear LCD Customer Display, the API sets REAR_IE# low
at U47-10, placing data from the rear display at U47-9 on at
MSR_REAR_RX
U47-8, where it is fed to the COM3 UART in U15.
To receive data from a Pole LCD Customer Display, the API sets POLE_IE# low
at U47-1, placing data from the pole display at U47-2 on at
MSR_REAR_RX
U47-3.
Once the display update cycle is compete, the API switches the interface speed
from 115K to 9600 baud, enables the MSR Interface and sends the reader an XON
command. If a card swipe occurred during the update cycle, the MSR forwards the
card data to the API.
Rear LCD Customer Display Firmware Programming
Referring to Figure 2-24, note the addition of two pins to J1, the Rear Display
connector.
The LCD Customer Display, (Rear or Pole Mount) contains a microcontroller
with on-board flash EEPROM for firmware storage. The firmware can be
reprogrammed to support new features or to correct program bugs.
WS4 Diagnostics Utility Version 1.90 or later and WS4 System Board AB28-I are
at minimum, required to perform a LCD Customer Display firmware upgrade. In
addition to the capability to test all aspects of the Rear or Pole LCD, a single
button programs the firmware in the Rear LCD Customer Display connected to J1
on the System Board.
AB28-I System Board COM3 Multiplexer - Software Compatibility
In order for the COM3 Multiplexer to function, the GR 1.2 software platform or
later is required. Specifically, the WS4 API, UWS4.DLL in this release contains
the code to necessary to enable and control the multiplexer operation. If the
correct version of API is not installed, both the MSR and Customer Display
Interfaces stop functioning.
The ABRD36 System Board, the last system board produced for the original
Workstation 4 also includes the COM3 mux and requires the GR2.2 platform to
function correctly.
Workstation 4 and 4 LX Field Service Guide 2-43