Xerox WorkCentre XK50cx, Service Manual

Page: 41 / 109

4-1-6 USB CONTROLLER
4-1-6-1. CONCEPT
USB Controller is an interface part specifically
designed to support to support a needed protocol to
transfer between the data and PC. The data can
either from PC printing data and / or inputted
document data from any other means.
4-1-6-2. UNICON : 23USB CONTROLLER
4-1-6-3. FEATURES
4-1-6-4. FEATURES
• /IRQ : excluding IMAGE DATA, all PROTOCOL
and ERROR signals and related PROCESSES are
taken care of by INTERRUPTOR.
• DMA : both input and printable IMAGE DATA will
be process by DMA
4-1-6-5. INTERFACE DIAGRAM
• VBUS : UNICON VBUS INPUT PIN (U23-16) can
detect and confirm with HARDWARE whether USB
CABLE is properly connected by checking the
presence of +5V from PC. Our main controller
does not use VBUS for the current. Furthermore, If
there is no current flow in the R58 and R59 (Driver
PBA) then +5V will shut off to feed UNION.
• D+, D- : PC and UNICON, are Differential Data
Bus, that send a Protocol and DATA signal to each
other.
• USB SPECIFICATION VERSION 1.1 SUPPORT
• FULL SPEED DEVICE : 12MBPS
• 5V I/O PIN INTERFACE (3.3V REGULATOR BULT-IN)
• CONTROL, INTERRUPT AND BULK TRANSFER
SUPPORT
• SUPPORTS 4 ENDPOINTS
• DMA INTERFACE SUPPORT TO TRANSFER
BULK ENDPOINT
• 128 BYTE RECEIVER, TRANSMIT FIFOs BUILT-IN
• DUAL-PACKET MODE(FIFO) SUPPORT
• SUSPEND AND REMOTE WAKE-UP CAPABILITY
SUPPORT
• FREQUENCY : 48MHz
The true signal level is 3.3V peak-to-peak. In order
to begin movement at FULL SPEED MODE,
D+(USBDP) Pin should be set and maintained at
USB CABLE’s connection and movement speed
conditions. R86 and R107 (Driver PBA) are there
to USB IMPEDANCE MATCHING purpose
• PULLUP : If USB CABLE is connected to the main
controller then UNICON can recognize the CABLE
connection through CONNECTOR (CN11 : Driver
PBA)’s VBUS and +3.3V becomes PULLUP PIN.
In order for PC to know the FULL SPEED MODE,
D+’s R85 PULLUP is and absolute necessity.
• CN114(Driver PBA) : For our main controller
system, all GND should be connected as fixed
wire mode to maintain the best possible condition.
FGND : FRAME GROUND. SGND : FRAME
GROUND POINT WITH BOLT.
4-14
Circuit