Motorola PowerQUICC II MPC8280 Series Reference Manual page 876

USB Host Description
27.5.7.1 USB Mode Register (USMOD)
USMOD, shown in Figure 27-10, controls the USB controller operation mode.
0
Field LSS RESUME
Reset
R/W
Addr
Table 27-9 describes USMOD fields.
Bits Name
0 LSS Low-speed signaling. Selects the signaling speed. The actual bit rate depends on the USB
clock source.
0 Full-speed (12-Mbps) signaling. Normal operation.
1 Low-speed (1.5-Mbps) signaling. For a point-to-point connection with a low-speed device or
for local loopback testing.
1 RESUME Generate resume condition. When set, this bit generates a resume condition on the USB. This
bit should be used if the function wants to exit the suspend state.
2–3 — Reserved, should be cleared.
4 SFTE Start-of-Frame Timer Enable. Setting this bit enables the Start-of-Frame timer and automatic
SOF transmission. See Section 27.5.7.8, "USB Start of Frame Timer (USSFT)" and
Section 27.5.2, "SOF Transmission for USB Host Controller" for more information.
0 SOF timer is disabled
1 SOF timer is enabled
Note: When SFTE is 1, the PC21 pin cannot be used as CP_INT since the CP interrupt is used
internally for generating the SOF packet.
5 TEST USB controller test (loopback) mode
0 Test mode is disabled
1 Test mode is enabled
Note: This bit may be set only when HOST is set (USB host mode)
6 HOST USB host mode
0 USB host is disabled
1 USB host is enabled
7 EN Enable USB. When the EN bit is cleared, the USB is in a reset state
0 USB is disabled
1 USB is enabled
Note: Setting this bit automatically disables SCC4.
Note: Other bits of the USMOD should not be modified by the user while EN is set.
27.5.7.2 USB Slave Address Register (USADR)
The USB address register is an 8-bit, memory-mapped register. It holds the address for this
USB port when operating as function.
27-18
Freescale Semiconductor, Inc.
1 2
—
Figure 27-10. USB Mode Register (USMOD)
Table 27-9. USMOD Fields
MPC8280 PowerQUICC II Family Reference Manual
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3 4 5
SFTE TEST
0000_0000
R/W
0x11B60
Description
6 7
HOST EN
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