Nellcor N-180 Service Manual page 28

Section 3: Functional Block and Circuit Analysis
VCALI 3 „U2A 2
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ili
RED_ADC 14 = 15
wi. 16 M
IR ADC U24C
\ ( А 11 へ 2410
ον 915
20
0240 19 020
VCAL 2 7 6 à σι] 24 Dual
ΨΑ 81 Channel
bt Sod Sera
RESISTORS 13 Output
6 15
U19
2.5V Ref ADCDATA
一 一 一 一 一 ADCCHN
REF2.5
Figure 3-5: Oximetry Module Analog to Digital Conversion Circuits
: Support Circuits
Support circuits include the following:
e Communications
Processor circuits
e Power
- m © Communications:
The oximetry module CPU (figure 3-6) manages communications to
'other monitor electronics. There are two data signals (RXD, TXD) and
three control signals at. the module connection to the CPU PCB.
CTS* clear to send is a logic signal (active low) transmitted to the oximetry
module by the monitor to suspend data transmission from the module
RESET* is an input (active low) from the main processor to effect a reset in the
oximetry module
RXD is the receive data line from the CPU PCB
TXD is the transmitted data line to the CPU PCB
C-LOCK
external synchronizing signal from ECG monitor (not used)
3-13