Schiller AT-102, Service Handbook, Page: 132 / 140

Annex
A.6
AT-102 Service Handbook
SC(0..8) System control bus - CPU control signals
SCINV Screen inversion.
SO Serial output from the CPU to the ECG amplifier via opto isolators.
SP.. Spirometry control and data signals.
SRAM Static RAM memory.
STRB1/2 Timing signals for printer control.
SYSEN System enable - active when the Program Pack is inserted. The CPU will not work if
this signal is not active.
TGATE Gate pulse for programmable timer. This signal sets the TPDUR signal.
TM Thermal printer temperature - dc voltage from the print head, pulse width modulation
of signal TPTH.
TPC Thermal printer clock. This is not a continuous clock signal but is active when
loading a line of printer data (into shift registers).
TPCLK Thermal printer clock.
TPD Thermal printer data - serial data for the printer.
TPDUR Thermal printer duration - duration of the strobe pulse dependant on the ambient
temperature of the print head and the resistance of the print head.
TPCSEL Thermal printer controller select - control of thermal printer FIFO (input memory
buffer).
TPL Thermal printer latch - print strobe control and data latch signal.
TPRES Thermal printer reset - FIFO reset for thermal printer controller.
TPS 0 & 1 Thermal printer strobe.
TPTH Thermal printer temperature - dc voltage from the print head to ADC, approximately
3.7 V at room temperature.
TS Temperature sense (from battery).
TXD Outgoing serial data.
uPOFF Off control signal. Logic 1 keeps the unit switched on, logic 0 switches the unit off.
Note that the unit is initially switched on directly from the ON key on the keyboard.
U1,2,3,4 Upper LCD data.
+UB Battery voltage.
UCAS Upper column address strobe (for dynamic RAM).
UD1, UD2 Upper data strobe - used for generating UOE and UWE.
UDS Upper data strobe - used on the Schiller gate array.
UOE, USRAM Upper output enable - for static RAM.
+UP Voltage rectified from the mains input and regulated to approxi15 V.