MAS 3507D
PRELIMINARY DATA SHEET
2.9. Status Pins in SDI Input Mode
Table 2–9: PIO output signals during MPEG decoding
in SDI mode
After having read the start-up configuration, the PIO
will be switched to ‘µP-mode’. In µP-mode, the addi-
tional PIO control lines (PR, PCS) are evaluated. If the
MPEG decoder firmware detects PR = ‘1’ and the
PCS = ‘0’. Then, all PIO interface lines are configured
as output and display some status information of the
MPEG decoder. The PIO lines can be read by an
external controller or directly used by dedicated hard-
ware blocks (e.g. for sample rate indication or display
units). The internal MPEG decoder firmware attaches
specific functions to the following pins.
PIO
Pin
Name
Comment
PI19
Demand PIN
%0
%1
no input data exp.
input data request
PI18, MPEG INDEX
PI17
%00
MPEG 2.5
reserved
MPEG 2
MPEG 1
%01
%10
%11
The MPEG-FRAME-SYNC signal is set to ‘1’ after the
internal decoding for the MPEG header has been fin-
ished for one frame. The rising edge of this signal
could be used as an interrupt input for the controller
that triggers the read out of the control information and
ancillary data. As soon as the MAS 3507D has recog-
nized the corresponding read command (‘read control
interface data’ (see Section 3.3.2. on page 21), the
MPEG-FRAME-SYNC is reset. This behavior reduces
the possibility of missing the MPEG-FRAME-SYNC
active state.
PI13, MPEG Layer ID
PI12
%00
reserved
Layer 3
%01
%10
%11
Layer 2
Layer 11)
PI8
PI4
MPEG CRC-ERROR
%0
%1
no error
CRC-error,
MPEG decoding
not successful
tframe=24 ... 72 ms
tread
MPEG-FRAME-
SYNC
V
l
h
see following text
in kHz2)
PI3,
PI2
Sampling frequency
MPEG-FRAME-SYNC
%00
%01
%10
%11
44.1 / 22.1 / 11.0
48 / 24 / 12
32 / 16 / 8
Fig. 2–8: Schematic timing of MPEG-FRAME-Sync
reserved
The time tread depends on the response time of the
controller. This time must not exceed 1/2 of the MPEG-
frame length tframe. The MPEG frame lengths are given
in Table 2–10
PI1,
PI0
Deemphasis
%00
%01
%10
%11
none
50/15 µs
reserved
CCITT J.17
1)
Layer 1 bit streams will not be decoded
Sampling frequency also defined by MPEG index
(see Table 3–12 for additional information)
2)
.
16
Micronas
MICRONAS [ MICRONAS ]
