Merge pull request #422 from xobs/core-doc-fixes

Core doc fixes
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Sean Cross 2020-03-11 19:38:42 +08:00 committed by GitHub
commit 01b6969375
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2 changed files with 13 additions and 17 deletions

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@ -11,9 +11,7 @@ from litex.soc.integration.doc import AutoDoc, ModuleDoc
class S7I2SSlave(Module, AutoCSR, AutoDoc):
def __init__(self, pads, fifo_depth=256):
self.intro = ModuleDoc("""
Intro
*******
self.intro = ModuleDoc("""Intro
I2S slave creates a slave audio interface instance. Tx and Rx interfaces are inferred based
upon the presence or absence of the respective pins in the "pads" argument.
@ -24,7 +22,7 @@ class S7I2SSlave(Module, AutoCSR, AutoDoc):
to a CODEC without a programmable bit offset!
System Interface
=================
----------------
Audio interchange is done with the system using 16-bit stereo samples, with the right channel
mapped to the least significant word of a 32-bit word. Thus each 32-bit word is a single
@ -61,7 +59,7 @@ class S7I2SSlave(Module, AutoCSR, AutoDoc):
in FIFO is cleared.
CODEC Interface
================
---------------
The interface assumes we have a sysclk domain running around 100MHz, and that our typical max
audio rate is 44.1kHz * 24bits * 2channels = 2.1168MHz audio clock. Thus, the architecture
@ -92,7 +90,6 @@ class S7I2SSlave(Module, AutoCSR, AutoDoc):
- Sync can be longer than the wordlen, extra bits are just ignored
- Tx is data to the codec (SDI pin on LM49352)
- Rx is data from the codec (SDO pin on LM49352)
""")
# One cache line is 8 32-bit words, need to always have enough space for one line or else

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@ -18,9 +18,7 @@ class S7SPIOPI(Module, AutoCSR, AutoDoc):
sim = False,
spiread = False,
prefetch_lines = 1):
self.intro = ModuleDoc("""
Intro
********
self.intro = ModuleDoc("""Intro
SpiOpi implements a dual-mode SPI or OPI interface. OPI is an octal (8-bit) wide variant of
SPI, which is unique to Macronix parts. It is concurrently interoperable with SPI. The chip
@ -300,14 +298,13 @@ class S7SPIOPI(Module, AutoCSR, AutoDoc):
),
]
self.architecture = ModuleDoc("""
Architecture
**************
self.architecture = ModuleDoc("""Architecture
The machine is split into two separate pieces, one to handle SPI, and one to handle OPI.
SPI
=====
-----
The SPI machine architecture is split into two levels: MAC and PHY.
The MAC layer is responsible for:
@ -333,7 +330,8 @@ class S7SPIOPI(Module, AutoCSR, AutoDoc):
Thus holding "req" high can allow the PHY to back-to-back issue cycles without pause.
OPI
=====
-----
The OPI machine is split into three parts: a command controller, a Tx PHY, and an Rx PHY.
The Tx PHY is configured with a "dummy cycle" count register, as there is a variable length
@ -389,6 +387,7 @@ class S7SPIOPI(Module, AutoCSR, AutoDoc):
- pre-fetch is aborted because bus_adr and next read address don't match and FIFO is reset
RxPHY:
- while CTI==2, assemble data into 32-bit words as soon as EMPTY is deasserted,
present a bus_ack, and increment the next read address pointer
- when CTI==7, ack the data, and wait until the next bus cycle with CTI==2 to resume