Chapter 3
Hardware
MightyBoard 821
Reference Manual
21
Mouse Interface
The Super I/O chip (W83627HF) provides the signal lines for a PS/2 mouse through the mouse connector
(J1B).
USB Interfaces
The I/O Hub (82801DBM) provides the USB solution for both legacy UHCI controllers and EHCI controller
(USB 2.0) support. The I/O Hub (Southbridge) contains port-routing logic that determines which controller
(UHCI or EHCI) handles the USB data signals. The PC-style (or Standard) connector (J11 B and C)
provides two of the four USB ports, USB0 and USB1. The other PC-style (or Standard) connector (J13 B
and C) provides the other two USB ports, USB2 and USB3. The Super I/O provides USB 4 and 5 on the J21
header.
USB 2.0 Support
The I/O Hub (Southbridge) contains an Enhanced Host Controller Interface (EHCI) compliant host
controller, which supports up to four high-speed USB 2.0 Specification compliant root ports. The higher
speed USB 2.0 specification allows data transfers up to 480 Mbps using the same pins as the four full-speed/
low-speed USB UHCI ports. The I/O Hub (Southbridge) port-routing logic determines which of the
controllers (UHCI or the EHCI) processes the USB signals. The Super I/O provides USB 4 and 5 on the J21
header.
•
One EHCI host controller for all four USB ports on connectors
•
Supports USB v2.0 Specification
•
Over-current fuses, located on the board, where USB0 and USB1 share a single fuse (F2), USB2 and
USB3 share a single fuse (F4), and USB4 and USB5 share a single fuse (F1). See
Table 2-3 on page 10
.
Legacy USB Support
The I/O Hub (Southbridge) supports two USB Universal Host Controller Interfaces (UHCI) and each Host
Controller includes a root hub with two separate USB ports each, for a total of four USB ports. The USB
Legacy features implemented in the USB ports include the following:
•
One root hub and two USB ports on connector
•
One root hub and two USB ports on connector
•
Supports USB v1.1 and UHCI v1.1 with integrated physical layer transceivers
•
Supports improved arbitration latency for UHCI controllers
•
UHCI controllers support Analog Front End (AFE) embedded cell instead of USB I/O buffers to allow
for USB high-speed signaling rates
•
Three shared over-current fuses, located on the board, are used on all six USB ports
USB4 and USB5
Table 3-6
describes USB 4 & 5 J21 with 10-pins, two rows, Odd/even (1, 2) and 2mm pin spacing.
Table 3-6. USB Ports 4 & 5 Interface Pin/Signal Descriptions (J21)
Pin #
Signal
Description
1, 2
+5V
+5V through a fuse (F3). Also over current monitor line.
3
USBP3-
Universal Serial Bus 2 Negative
5
USBP3+
Universal Serial Bus 2 Positive
4
USBP4-
Universal Serial Bus 3 Negative
