Usb Port; Rs-232 Port - Intermec CK30 Service Manual

Dock Interface Signal Descriptions (continued)
Signal
Pin Name
TETH_PRE
12
SENT
22 TX+
23 TX-
24 RX+
25 RX-

USB Port

RS-232 Port

CK30 Handheld Computer Service Manual
Description
Scanner interlock to mux internal and external
undecoded scanners.
0 = undecoded scanner present
1 = no undecoded scanner present
Ethernet TX+
Ethernet TX-
Ethernet RX+
Ethernet RX-
The CK30 supports USB 1.1 (12Mbps) client functionality through the
USB_D+, USB_D- and USB_5V signals on dock interface connector J13.
The USB client controller is built into the PXA255 processor (U2). When
the USB connection is used for serial port emulation, the operating system
maps it as COM1.
USB_5V (the 5V power supplied by the USB host) is used only to detect
the presence of a USB host; it is not used to power any CK30 hardware. It
is divided down to 3.3V levels by R157 and R160, and routed (as signal
USB_WAKE) to PXA255 interrupt input GPIO19. The USB software
driver responds to the interrupt by trying to connect to a USB host
through the PXA255 client controller.
If the CK30 is suspended, USB_WAKE can be configured to wake the
system through the DOCK_WAKE path: a high-going transition on
USB_WAKE propagates through U24, is debounced by R274, C147 and
U33, and then is differentiated by C180 and R321. The resulting pulse
goes through the resume logic on PXA255 GPIO1 (see "Resume Events"
on page 65), waking the system if this wakeup is enabled (HCR U16
output RESUME_EN is high).
This feature is not supported in the current software.
Note that this wakeup method can be inhibited through U24 if the dock
port serial DCD is asserted (so CD_WAKE is high). But in most cases this
means the CK30 is already awake.
The CK30 supports RS-232 communications through the serial signals on
dock interface connector J13. The signals are converted to true RS-232
levels by U23, and brought to the "FF" UART built into the PXA255
processor. The operating system maps this port as COM2.
Chapter 4 — Theory of Operation
Signal Characteristics
3.3V CMOS
89