
Philips Semiconductors
Audio In
PRODUCT SPECIFICATION
8-5
Note that the AI hardware does
not generate A-law or
-
law 8-bit data formats. If such formats are desired, the
DSPCPU can be used to convert from 16-bit linear data
to A-law or
-law data.
8.7
AUDIO IN OPERATION
Figure 8-5, Table 8-9 and Table 8-8 describe the func-
tion of the control and status fields of the AI unit. To en-
sure compatibility with future devices, undefined bits in
MMIO registers should be ignored when read, and writ-
ten as ’0’s.
The AI unit is reset by a TM1300 hardware reset, or by
writing 0x80000000 to the AI_CTL register. Upon RE-
SET, capture is disabled (CAP_ENABLE = 0), and
buffer1 is the active buffer (BUF1_ACTIVE=1). A mini-
mum of 5 valid AI_SCK clock cycles is required to allow
internal AI circuitry to stabilize before enabling capture.
This can be accomplished by programming AI_FREQ
and AI_SERIAL and then delaying for the appropriate
time interval.
Programing of the AI_SERIAL MMIO register needs to
follow the following sequence order:
Table 8-6. AI MMIO DMA control elds
Field Name
Description
LITTLE_ENDIAN
0
capture in big endian memory format
(RESET default)
1
capture little endian
BASE1
Base address of buffer1; a 64-byte aligned
address in local SDRAM.
RESET default 0.
BASE2
Base address of buffer2; a 64-byte aligned
address in local SDRAM.
RESET default 0.
SIZE
Number of samples to be placed in
buffer before switching to other buffer
Stereo modes: a pair of 8- or 16-bit data
is 1 sample
Mono modes: a single value is 1 sample
RESET default 0.
CAP_MODE
00
mono (left ADC only), 8 bits/sample.
(RESET default).
01
stereo, 2 times 8 bits/sample
10
mono (left ADC only), 16 bits/sample
11
stereo, 2 times 16 bits/sample
SIGN_CONVERT
0
leave MSB unchanged (RESET
default)
1
invert MSB
Figure 8-5. AI status/control field MMIO layout.
MMIO_base
offset:
AI_STATUS (r/w)
0x10 1C00
AI_CTL (r/w)
0x10 1C04
AI_SERIAL (r/w)
0x10 1C08
SCKDIV
AI_FRAMING (r/w)
0x10 1C0C
AI_FREQ (r/w)
0x10 1C10
AI_BASE1 (r/w)
0x10 1C14
FREQUENCY
BUF1_ACTIVE
AI_BASE2 (r/w)
0x10 1C18
BASE2
AI_SIZE (r/w)
0x10 1C1C
SIZE (in samples)
31
0
3
7
11
15
19
23
27
VALIDPOS
BASE1
OVERRUN
HBE (Highway bandwidth error)
BUF2_FULL
RESET
CAP_ENABLE
CAP_MODE
SIGN_CONVERT
LITTLE_ENDIAN
0
DIAGMODE
OVR_INTEN
HBE_INTEN
BUF2_INTEN
BUF1_INTEN
ACK_OVR
ACK_HBE
ACK2
ACK1
WSDIV
SER_MASTER
DATAMODE
FRAMEMODE
POLARITY
LEFTPOS
RIGHTPOS
SSPOS
0
BUF1_FULL
SLEEPLESS
CLOCK_EDGE
0
31
0
3
7
11
15
19
23
27
31
0
3
7
11
15
19
23
27
31
0
3
7
11
15
19
23
27
31
0
3
7
11
15
19
23
27
RESERVED