2 parallel data formats for fifo storage, Parallel data formats for fifo storage -6, National microwire* frame format -6 – Intel PXA255 User Manual
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8-6
Intel® PXA255 Processor Developer’s Manual
Synchronous Serial Port Controller
shows the National Microwire frame format with 8-bit command words for single and
back-to-back frame transmissions.
8.4.2
Parallel Data Formats for FIFO Storage
Data in the FIFOs is stored with one 16-bit value per data sample with no regard to the format’s
data word length. In each 16-bit field, the stored data sample is right-justified, the word’s least
significant bit is stored in bit 0, and unused bits are packed as zeroes above the most significant bit.
Logic in the SSPC automatically left-justifies data in the Transmit FIFO so the sample is properly
transmitted on SSPTXD in the selected frame format.
Figure 8-3. National Microwire* Frame Format
SSPSCLK
...
...
SSPSFRM
...
...
SSPTXD
Bit<7>
...
Bit<0>
...
8-Bit Control
1 Clk
SSPRXD
...
Bit<N>
...
Bit<0>
4 to 16 Bits
Single Transfer
SSPSCLK
...
...
...
SSPSFRM
...
...
...
SSPTXD
Bit<0>
...
Bit<7>
...
Bit<0>
...
1 Clk
1 Clk
SSPRXD
Bit<N>
...
Bit<0>
...
Bit<N>
...
Bit<0>
Continuous Transfers