W90221X Winbond Electronics Corp America, W90221X Datasheet - Page 39

• Manufacturer Part Number: W90221X
• Description: Pa-risc Embedded Controller
• Manufacturer: Winbond Electronics Corp America

5.13 Synchronous Serial interface (SSI)
5.13.1 Overview
The SSI module within W90221X contains holding registers, shift registers, and other logic to
support a variety of serial data communications protocols and provide a direct connection to
external audio/telephony codec devices. Two 48-half-word FIFOs, one transmitter FIFO and
one receiver FIFO, have been implemented to accelerate both transmitting and receiving
operations. These two FIFOs can be configured as 48 half-word or 24 words depth depending
on the data word length.
5.13.2 Block Diagram
Figure 5.13.2.1 Block diagram of SSI
5.13.3 Features
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5.13.4 Related Pins
SDI (input)
SDO (output)
SYNC (in/out)
W90221X version 0.6
Supports "long framing" and "short framing" (synchronous, frame-based protocol)
Provides "master mode" and "slave mode"
Build-in two 48x16 (or 24x32) data FIFOs accelerating transmit/receive operation
Programmable data bits per one frame (sampling rate) : 1 ~ 256 bits/frame
Programmable data bits per word (resolution of each sampling) : 1 ~ 32 bits/word
Programmable multi-word (per frame) transfer : 1 ~ 16 words/frame
This pin contains the input data shifted from external audio/telephony codec devices.
This pin contains the output data shifted to external audio/telephony codec devices.
This pin is the frame synchronization signal between SSI and codec devices. The SYNC
may be input or output depending on SSI operated in slave- or master-mode
respectively.
LSR[1] will indicate that both TX-FIFO and shift register are empty.
LSR[0] will indicate whether there are any errors in the RX-FIFO.
SDO
32-bit TX-Shift reg
(48x16/24x32)
TX-FIFO
16/32
16/32
32-bit CPU bus
SYNC SCLK
& Shift-in/out
SCLK/SYNC
FIFO Control
control
Logic
32-bit RX-Shift reg
(48x16/24x32)
RX-FIFO
16/32
16/32
SDI
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