Service manual

16 Channel Digital I/O Interface Card (SMN812-312)
CARD DESCRIPTION
Up to 4 cards can be fitted on to the AES960 motherboard, this gives a maximum of 56 Input
/ 56 Output, AES mono channels.
The I/O card provides 8 stereo channels of AES3 digital inputs with sample rate converters
and 8 stereo channels of AES3 digital outputs with sample rate converters. The digital
signals should be at a sample rate of 44.1khz to 96khz at an impedance of 110 W ± 20%.
Each stereo digital input can be fed directly to the MADI output stream or through a sample
rate converter with a 3:1 sample rate ratio.
Each stereo digital output can be fed directly from the MADI input stream or through a
sample rate converter with a 3:1 sample rate ratio.
Each stereo digital output can be synchronized to the AES input clock source in blocks of 4
stereo channels, to the AES960 sync source clock or to any of the 4 internal clocks.
All of these options can be set using the AES960 front panel button display or via a suitable
Ch55 MADI stream from an AMS console.
Internally the card is controlled by RS485 from the Host micro controller on the
motherboard, this is separate to the RS485 signal on the AES960 rear panel.
Jumper LK1 to LK8 introduce digital input signal equalization when removed, these should
be fitted for normal operation with AES cables up to 100 meters.
The board has 2 LEDs which will flash in normal operation, these are driven by a
ATmega128 micro controller (uP).
A 10 way Dubox connector is fitted for in-system programming of micro controller only. An
8 way Dubox connector is fitted for in-system programming of PLDs only.
LED INTERPRETATION
D2 (green) ON indicates the card is working
D1 (green) ON indicates communication with the
Host micro controller
SW1 This is for development only, it resets the micro
controller
Digital Service Manual
Issue 3 Page 39