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| author | Marti Bolivar <mbolivar@leaflabs.com> | 2011-05-27 18:55:57 -0400 |
|---|---|---|
| committer | Marti Bolivar <mbolivar@leaflabs.com> | 2011-05-27 18:55:57 -0400 |
| commit | eee36ecb65ec8d8e032886468e22d941cc3239c9 (patch) | |
| tree | 4adcbffd7707ef41894921ddbb3510e4ce601052 /docs | |
| parent | 9595ce520a6be0d993e87d80bed9fc47e7c203ba (diff) | |
| download | librambutan-eee36ecb65ec8d8e032886468e22d941cc3239c9.tar.gz librambutan-eee36ecb65ec8d8e032886468e22d941cc3239c9.zip | |
Docs: Correct i2c.rst errors.
10-bit addressing has now been implemented. Slave mode is
unimplemented, however.
Diffstat (limited to 'docs')
| -rw-r--r-- | docs/source/i2c.rst | 21 |
1 files changed, 11 insertions, 10 deletions
diff --git a/docs/source/i2c.rst b/docs/source/i2c.rst index 31976ac..8f1b26f 100644 --- a/docs/source/i2c.rst +++ b/docs/source/i2c.rst @@ -7,17 +7,18 @@ two wires/channels for communication between many devices. Every message passed on the bus is between a *master* (who initiates the message) and a *slave* device. Slaves are addressed using 7-bit -addresses (up to 127 unique devices); 10-bit addressing is possible, -but currently unimplemented. Every message consists of an arbitrary -combination of 8-bit reads and writes as requested by the master. -Higher level functionality, such as reading a particular register -value, is achieved by writing to set the memory location then reading -to pull out the data. +addresses (up to 127 unique devices); 10-bit addressing is also +possible. Every message consists of an arbitrary combination of 8-bit +reads and writes as requested by the master. Higher level +functionality, such as reading a particular register value, is +achieved by writing to set the memory location then reading to pull +out the data. Note that the master/slave designation is on a message-by-message basis. Maple can act as both a master (messages initiated by user code) and slave device (responding to requests via configurable -interrupt handlers) at the same time. +interrupt handlers) at the same time (though slave mode is currently +unimplemented). .. contents:: Contents :local: @@ -28,10 +29,10 @@ Hardware/Circuit Design .. FIXME [0.1.0] Link to board-specific values (BOARD_I2C1_SDA_PIN, etc.) Maple boards have two |i2c| ports. Maples reliably communicate with -up to a 400kHz clock speed; this doesn't translate into a 400kbps data -rate except in extreme cases because of addressing and protocol +up to a 400kHz clock speed; this doesn't translate into a 400kbps +data rate except in extreme cases because of addressing and protocol overhead. We have tested clock speeds up to a megahertz and have had -mixed results; in theory it could be possible to achieve even higher +mixed results; in theory, it could be possible to achieve even higher rates, but signal quality degrades rapidly, and the bus becomes unreliable. |