Freescale Semiconductor PowerQUICC MPC885 Reference Manual page 867

Bits Name
12–13 THS Transmit hand shake for USB function controller
00 Normal handshake
01 Ignore IN token
10 Force NACK handshake. Not allowed for
11 Force STALL handshake. Not allowed for
14–15 RHS Receive hand shake for USB function controller
00 Normal handshake
01 Ignore OUT token
10 Force NACK handshake. Not allowed for
11 Force STALL handshake. Not allowed for
31.11.4 USB Command Register (USCOM)
USCOM is used to start USB transmit operation.
Field STR
Reset
R/W
Addr
Table 31-11 describes USCOM fields.
Bits Name
0 STR
1 FLUSH
2–5 —
6–7 EP
Freescale Semiconductor
Table 31-10. USEPx Fields (continued)
USB function mode description
control endpoint.
control endpoint.
control endpoint.
control endpoint.
0 1 2
FLUSH
Figure 31-15. USB Command Register (USCOM)
Table 31-11. USCOM Fields
Start FIFO fill. Setting the STR bit to one causes the USB controller to start the filling the
corresponding endpoint transmit FIFO with data. Transmission will begin once the IN token
for this endpoint is received. The STR bit is read always as a zero.
Flush FIFO. Setting the FLUSH bit to one causes the USB controller to flush the
corresponding endpoint transmit FIFO. Before flushing the FIFO, the user should issue the
Stop_Tx command. After flushing the FIFO the user should issue the Restart_Tx command
(Refer to Section 31.13, "USB CP
Reserved, should be cleared.
Endpoint. Selects one of the four supported endpoints.
MPC885 PowerQUICC Family Reference Manual, Rev. 2
USB host mode description
Transmit hand shake for USB host controller
00 Normal handshake
Receive hand shake for USB host controller
00 Normal handshake
5
—
0000_0000
R/W
0xA02
Description
Commands."). FLUSH is always read as a zero.
Universal Serial Bus (USB)
6 7
EP
31-19