Data Sheet
June 2001
DSP16410B Digital Signal Processor
168
Agere Systems—Proprietary
Use pursuant to Company instructions
Agere Systems Inc.
4 Hardware Architecture
(continued)
4.16 Serial Interface Unit (SIU)
(continued)
4.16.12 Channel Mode—32 Channels or Less in
Two Subframes or Less
Compared to frame mode, channel mode provides for
channel selectivity with minimal core overhead at the
expense of channel density. For input, this mode is
selected if the following conditions are met:
The IFRAME field (
SCON1
[7]—see
Table 102 on
page 183
) is cleared.
The ISFIDV_E field (
SCON3
[2]—see
Table 104 on
page 185
), the ISFIDV_O field (
SCON3
[5]), or both
are set.
For output, channel mode is selected if the following
conditions are met:
The OFRAME field (
SCON2
[7]—see
Table 102 on
page 183
) is cleared.
The OSFIDV_E field (
SCON3
[10]), the OSFIDV_O
field (
SCON3
[13]), or both are set.
In this mode, the SIU processes a maximum of 32
channels within a given frame. The maximum frame
size is 128 channels. The IFLIM[6:0] field
(
SCON1
[6:0]—
Table 102 on page 183
) for input and
the OFLIM[6:0] field (
SCON2
[6:0]—
Table 103 on
page 184
) for output define the number of channels in
the frame structure.
To assist with channel selection, both input and output
frames are divided into eight subframes: four even (0,
2, 4, 6) and four odd (1, 3, 5, 7). The SIU can enable
only one even and one odd subframe at any one time.
Each subframe contains 16 channels
1
that can be indi-
vidually enabled.
Figure 49
shows a 128-channel
frame and the relationship between frames, subframes,
and logical channels.
Table 92 on page 169
specifies
the association of channel numbers to even and odd
subframes.
Channel Mode on a 128-Channel Frame
Figure 49. Channel Mode on a 128-Channel Frame
1. It is assumed that for channel mode, the number of channels per frame as determined by the IFLIM[6:0] and OFLIM[6:0] fields is evenly divis-
ible by 16. This results in exactly 16 channels per subframe. If the number of channels per frame is not evenly divisible by 16, the last sub-
frame is a partial subframe of less than 16 channels. If this is the case and if interrupts are programmed to occur on subframe boundaries
(see
Figure 51 on page 175
), then an interrupt is not generated for the partial subframe.
15
13
2
1
14
13
SYNC
DATA
128-CHANNEL FRAME
I,O
FLIM = 0x7F
I,O
FRAME = 0x0
; DEFINE AS 128-CHANNEL FRAME
; TRANSFER ONLY SELECTED CHANNELS
8 SUBFRAMES PER TDM FRAME
16 CHANNELS PER SUBFRAME
[0:15]
[16:31]
[112:127]
[96:111]
[80:95]
[64:79]
[48:63]
[32:47]
SUBFRAME 2
SUBFRAME 5
0
0
0
1
2
13
14
I,O
SFID_E = 1
I,O
SFIDV_E = 1
I,O
SFVEC_E = 0xFFFF
OSFMSK_E = 0x7FF9
CHANNEL DATA BITS
; SUBFRAME 2 SELECTED
; ALLOW INDIVIDUAL CHANNEL SELECTION
; ALL 16 CHANNELS ACCESSIBLE
; MASK ALL OUTPUT CHANNELS
; EXCEPT 15, 2, 1
I,O
ISIZE = 1
I,O
MSB = 1
; 16-BIT CHANNELS
; MSB SHIFTED FIRST
ACTIVE CHANNELS
MASKED CHANNELS
CHANNEL DATA BITS
15
1
2
15
0
14
EVEN
SUBFRAME
ODD
SUBFRAME
ODD
SUBFRAME
ODD
SUBFRAME
EVEN
SUBFRAME
EVEN
SUBFRAME
EVEN
SUBFRAME
ODD
SUBFRAME
I,O
SFID_O = 2
I,O
SFIDV_O = 1
I,O
SFVEC_O = 0xFFFF
OSFMSK_O = 0xBFFD
; SUBFRAME 5 SELECTED
; ALLOW INDIVIDUAL CHANNEL SELECTION
; ALL 16 CHANNELS ACCESSIBLE
; MASK ALL OUTPUT CHANNELS
; EXCEPT 1 AND 14
16 BITS PER CHANNEL