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authorIztok Jeras <iztok.jeras@gmail.com>2012-07-17 19:33:44 +0200
committerIztok Jeras <iztok.jeras@gmail.com>2012-07-17 19:33:44 +0200
commit4633e258a4885a455a82c32548f7bb4d4b293e2e (patch)
tree5828573fb07aeb3af08e7c7e2df84bc607bd9538 /decoders/onewire_network
parenta81787f62362e7ab8471c4c01baa6a806d624d58 (diff)
downloadlibsigrokdecode-4633e258a4885a455a82c32548f7bb4d4b293e2e.tar.gz
libsigrokdecode-4633e258a4885a455a82c32548f7bb4d4b293e2e.zip
onewire: updated documentation
Diffstat (limited to 'decoders/onewire_network')
-rw-r--r--decoders/onewire_network/__init__.py61
1 files changed, 19 insertions, 42 deletions
diff --git a/decoders/onewire_network/__init__.py b/decoders/onewire_network/__init__.py
index 991919f..56a5eb5 100644
--- a/decoders/onewire_network/__init__.py
+++ b/decoders/onewire_network/__init__.py
@@ -23,54 +23,31 @@
The 1-Wire protocol enables bidirectional communication over a single wire (and
ground) between a single master and one or multiple slaves. The protocol is
-layered, the provided parser decodes the next layers:
+layered.
- Link layer (reset, presence detection, reading/writing bits)
-- Network layer (skip, search, match device ROM addresses)
-The higher layers (transport, presentation) are not decoded, since they are
-mostly device specific and it would take a lot of code to interpret them.
+- Network layer (skip/search/match device ROM addresses)
+- Transport layer (transfer data between 1-Wire master and device)
-Sample rate:
-A high enough sample rate is required to properly detect all the elements of
-the protocol. A lower sample rate can be used if the master does not use
-overdrive communication speed. The next minimal values should be used:
-- overdrive available: 2MHz minimum, 5MHz suggested
-- overdrive not available: 400kHz minimum, 1MHz suggested
-
-Probes:
-1-Wire requires a single signal, but some master implementations might have a
-separate signal use to deliver power to the bus during temperature conversion
-as an example. This power signal is currently not parsed.
-- owr (1-Wire bus)
-- pwr (1-Wire power)
-
-Options:
-1-Wire is an asynchronous protocol, so the decoder must know the sample rate.
-The timing for sampling bits, presence and reset is calculated by the decoder,
-but in case the user wishes to use different values, it is possible to
-configure the next timing values (number of sample rate periods):
-- overdrive (if active the decoder will be prepared for overdrive)
-- cnt_normal_bit (time for normal mode sample bit)
-- cnt_normal_presence (time for normal mode sample presence)
-- cnt_normal_reset (time for normal mode reset)
-- cnt_overdrive_bit (time for overdrive mode sample bit)
-- cnt_overdrive_presence (time for overdrive mode sample presence)
-- cnt_overdrive_reset (time for overdrive mode reset)
-This options should be configured only on very rare cases and the user should
-read the decoder source code to understand them correctly.
+Network layer
Annotations:
-Annotations can be shown for each layer of the protocol separately:
-- link (the value of each transmitted bit is shown separately)
-- network (the ROM command, and address are shown)
-- transport (only transport layer byte transfers are shown)
-If link layer annotations are shown, possible issues with sample rate and sample
-timing are also shown.
+The next link layer annotations are shown:
+- RESET/PRESENCE True/False
+ The event is marked from the signal negative edge to the end of the reset
+ high period. It is also reported if there are any devices attached to the
+ bus.
+The next network layer annotations are shown:
+- ROM COMMAND val name
+ The requested ROM command is displayed as an 8bit HEX value and by name.
+- ROM val
+ The 64bit value of the addressed device is displayed:
+ family code (1B) + serial number (6B) + CRC (1B)
+- DATA val
+ Data intended for the transport layer is displayed as an 8bit HEX value.
TODO:
-- add CRC checks for network layer
-- add transport layer code
-- review link layer code, to check for protocol correctness
-- define output protocol
+- add CRC checks, to see if there were communication errors on the wire
+- add reporting original/complement address values from the search algorithm
'''
from .onewire_network import *