MAS3587F Micronas, MAS3587F Datasheet - Page 71

• Manufacturer Part Number: MAS3587F
• Description: MPEG Layer 3 Audio Encoder/Decoder
• Manufacturer: Micronas

ADVANCE INFORMATION
4.6.3.7. PIO as Parallel Output Interface:
In encoding mode, the MAS 3587F signals available
data by setting the EOD pin to ”high”. After verifying
this, the controller signalizes its capability to receive
one byte of data by activating the PR line. The
MAS 3587F responds by setting the RTW line to the
“low” level when the actual byte is set on the data lines
PI[19:12]. After PR is set to “low” level, the RTW line is
set to “high” again. The next data word write operation
will be initialized again by setting the PR line via the
controller. Please refer to Fig. 4–27 on page 71 for the
exact timing.
The procedure above will be repeated until the
MAS 3587F sets the EOD signal to “0” which indicates
that the transfer of one data block has been executed.
Subsequently, the controller should set PR to “0”, wait
until EOD rises again and then repeat the procedure to
receive the next block of data. The DMA buffer is
15 bytes long.
The buffer size is subject to change in the next version.
In order to transfer the worst case data rate of
192 kbit/s, the controller must react sufficiently fast.
The mean response times (t0, t3, t5) must be faster
than 10 ms. Due to internal buffering in the
MAS 3587F, this time can be expanded up to 4.8 ms
once within each frame (see Table 2–2 on page 15) in
any case.
Fig. 4–27: Handshake protocol for reading MPEG data from the PIO-DMA
Micronas
EOD
PR
RTW
PI[19:12]
DMA Mode
t
0
Byte 1
t
1
t
2
t
3
t
4
t
5
Table 4–5: PIO output mode timing
Symbol
t
t
t
t
t
t
t
t
0
1
2
3
4
5
eod
eodq
Byte 15
Pin
EOD, PR
PR, PI
PI, RTW
RTW, PR
PR, RTW
RTW, PR
t
eod
t
eodq
Min.
0.010
110
18
18
90
35
tbd
2.5
MAS 3587F
Max.
2000
310
55
260
tbd
high
high
low
high
low
high
low
low
Unit
ns
ns
ns
ns
ns
ns
ns
s
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