
OHCI Registers
172
September 2005
SCPS110
8.23 Isochronous Transmit Interrupt Event Register
The isochronous transmit interrupt event set/clear register reflects the interrupt state of the isochronous
transmit contexts. An interrupt is generated on behalf of an isochronous transmit context if an
OUTPUT_LAST* command completes and its interrupt bits are set to 1b. Upon determining that the isochTx
(bit 6) interrupt has occurred in the interrupt event register at OHCI offset 80h/84h (see Section 8.21), software
can check this register to determine which context(s) caused the interrupt. The interrupt bits are set to 1b by
an asserting edge of the corresponding interrupt signal, or by writing a 1b in the corresponding bit in the set
register. The only mechanism to clear a bit in this register is to write a 1b to the corresponding bit in the clear
register. See Table 817 for a complete description of the register contents.
OHCI register offset:
90h
set register
94h
clear register [returns the contents of the isochronous transmit interrupt
event register bit-wise ANDed with the isochronous transmit interrupt
mask register when read]
Register type:
Read/Set/Clear, Read-only
Default value:
0000 00XXh
BIT NUMBER
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RESET STATE
0
BIT NUMBER
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RESET STATE
0
X
Table 817. Isochronous Transmit Interrupt Event Register Description
BIT
FIELD NAME
TYPE
DESCRIPTION
318
RSVD
R
Reserved. Bits 318 return 00 0000h when read.
7
isoXmit7
RSC
Isochronous transmit channel 7 caused the interrupt event register bit 6 (isochTx) interrupt.
6
isoXmit6
RSC
Isochronous transmit channel 6 caused the interrupt event register bit 6 (isochTx) interrupt.
5
isoXmit5
RSC
Isochronous transmit channel 5 caused the interrupt event register bit 6 (isochTx) interrupt.
4
isoXmit4
RSC
Isochronous transmit channel 4 caused the interrupt event register bit 6 (isochTx) interrupt.
3
isoXmit3
RSC
Isochronous transmit channel 3 caused the interrupt event register bit 6 (isochTx) interrupt.
2
isoXmit2
RSC
Isochronous transmit channel 2 caused the interrupt event register bit 6 (isochTx) interrupt.
1
isoXmit1
RSC
Isochronous transmit channel 1 caused the interrupt event register bit 6 (isochTx) interrupt.
0
isoXmit0
RSC
Isochronous transmit channel 0 caused the interrupt event register bit 6 (isochTx) interrupt.
8.24 Isochronous Transmit Interrupt Mask Register
The isochronous transmit interrupt mask set/clear register enables the isochTx interrupt source on a
per-channel basis. Reads from either the set register or the clear register always return the contents of the
isochronous transmit interrupt mask register. In all cases the enables for each interrupt event align with the
isochronous transmit interrupt event register bits detailed in Table 817.
OHCI register offset:
98h
set register
9Ch
clear register
Register type:
Read/Set/Clear, Read-only
Default value:
0000 00XXh
BIT NUMBER
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RESET STATE
0
BIT NUMBER
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RESET STATE
0
X