C18 Models With A 28-Pin Interface Connector; Figure 33. Location Of The R6203 Resistor On The C18 - Motorola c18 Developer's Manual

Hardware Requirements for CDG2 and Field Testing
C.3

c18 MODELS WITH A 28-PIN INTERFACE CONNECTOR

c18 models that have a 28-pin interface connector, may be supplied in two configurations:
• With hardware preset for RS232 communication mode
• Without hardware preset for RS232 communication mode
The second configuration enables communicating via USB.
Integrators should prepare test connectors or test points for the following pins:
For Configuration:
• AUDIO_IN: Must be pulled down with 10
• USB_VBUS: Voltage (> 4 V) from the USB port must be present for configuring USB+RS232 mode (for configuration and
communication).
• OPT1: A 10kΩ pull-down resistor (R6203) on the c18 must be removed when using USB+RS232 mode. The location of the
R6203 resistor is shown in Figure 33. R6203 is not installed on c18 models that are not hardware configured for RS232
mode.
66
Ω to configure the c18 in USB+RS232 mode.
k

Figure 33. Location of the R6203 Resistor on the c18

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