Universal Serial Bus (USB)
MPC885 PowerQUICC Family Reference Manual, Rev. 2
31-20
Freescale Semiconductor
31.11.5 USB Event Register (USBER)
The USBER reports events recognized by the USB channel and generates interrupts. Upon recognition of
an event, the USB sets its corresponding bit in the USBER. Interrupts generated by this register may be
masked in the USB mask register.
The USBER may be read at any time. A bit is cleared by writing a one (writing a zero does not affect a
bit’s value). More than one bit may be cleared at a time. All unmasked bits must be cleared before the CP
will clear the internal interrupt request. This register is cleared at reset.
Table 31-12
describes USBER fields.
31.11.6 USB Mask Register (USBMR)
The USBMR is a 16-bit read/write register (0xA14) that has the same bit formats as the USB event register.
If a bit in the USBMR is one, the corresponding interrupt in the USBER is enabled. If the bit is zero, the
corresponding interrupt in the USBER will be masked. This register is cleared at reset.
0
5
6
7
8
9
10
11
12
13
14
15
Field
—
RESET IDLE TXE4 TXE3 TXE2 TXE1 SOF
BSY
TXB
RXB
Reset
0000_0000_0000_0000
R/W
R/W
Addr
0xA10
Figure 31-16. USB Event Register (USBER)
Table 31-12. USBER Fields
Bit
Name
Description
0 –5
—
Reserved, should be cleared.
6
RESET
Reset condition detected. USB reset condition was detected asserted.
7
IDLE
IDLE status changed. A change in the status of the serial line was detected. The real time
suspend status is reflected in the USB status register.
8–11
TXE
x
Tx error. An error occurred during transmission for endpoint x (packet not acknowledged or
underrun).
12
SOF
Start of frame. A start of frame packet was received. The packet is stored in the FRAME_N
parameter RAM entry.
13
BSY
Busy condition. Received data has been discarded due to a lack of buffers. This bit is set
after the first character is received for which there is no receive buffer available.
14
TXB
Tx buffer. A buffer has been transmitted. This bit is set once the transmit data of the last
character in the buffer was written to the transmit FIFO (if L=0 (last bit)) or after the last
character was transmitted on the line (if L=1).
15
RXB
Rx buffer. A buffer has been received. This bit is set after the last character has been written
to the receive buffer and the RxBD is closed.
Summary of Contents for PowerQUICC MPC870
Page 98: ...MPC885 PowerQUICC Family Reference Manual Rev 2 I 4 Freescale Semiconductor ...
Page 118: ...MPC885 Overview MPC885 PowerQUICC Family Reference Manual Rev 2 1 20 Freescale Semiconductor ...
Page 158: ...The MPC8xx Core MPC885 PowerQUICC Family Reference Manual Rev 2 3 18 Freescale Semiconductor ...
Page 288: ...MPC885 PowerQUICC Family Reference Manual Rev 2 III 4 Freescale Semiconductor ...
Page 554: ...MPC885 PowerQUICC Family Reference Manual Rev 2 V 6 Freescale Semiconductor ...
Page 1090: ...UTOPIA Interface MPC885 PowerQUICC Family Reference Manual Rev 2 43 8 Freescale Semiconductor ...
Page 1312: ...Byte Ordering MPC885 PowerQUICC Family Reference Manual Rev 2 A 8 Freescale Semiconductor ...
Page 1336: ...MPC885 PowerQUICC Family Reference Manual Rev 2 D 16 Freescale Semiconductor ...
Page 1358: ...MPC885 PowerQUICC Family Reference Manual Rev 2 D 38 Freescale Semiconductor ...
Page 1370: ...MPC880 MPC885 PowerQUICC Family Reference Manual Rev 2 E 4 Freescale Semiconductor ...
Page 1386: ...Revision History MPC885 PowerQUICC Family Reference Manual Rev 2 I 2 Freescale Semiconductor ...