960L Multi-Channel Digital Effects System Service Manual
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Local Loopback Mode:
When the local loopback mode bit is set in the FPGA control register, the AES inputs are looped through
the FPGA and back to the AES outputs. Also, the octal data received from the Reverb card is looped back
to the Reverb card by the FPGA as follows:
TMIX #2 octals 2 & 3 to TMIX #1 octals 10 & 0
TMIX #2 octals 8 & 9 to TMIX #1 octals 2 & 3
TMIX #2 octals 10 & 11 to TMIX #1 octals 11 & 1
Reverb card
Introduction
This section describes the theory of operation of the 960L Reverb Card.
Overview
The 960L Reverb Card is a 128 channel, 24 bit audio DSP processor that is the central DSP resource in the
960L system. Up to three of these cards can be inserted into the PCI bus for mixing, effects, and other
processing needs. The card has four Lexichip III reverb processors which are controlled by two Z-80
microprocessors. Audio mixing and the host interface are implemented with a Motorola 56301 DSP
microprocessor. Digital audio data is transferred to and from the card via the 960L I/O bus by two T-MIX
serial audio engines ASICs. The host Pentium microprocessor controls the I/O peripheral cards in the 960L
by sending commands through the Reverb card to the I/O bus. A third T-MIX ASIC is used to transfer serial
digital audio to and from the four Lexichip III chips. The 56301 reads and writes audio samples to the T-MIX
devices via a high-speed 24-bit data path.
Figure 1-1 is a block diagram of the 960L Reverb Card.
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