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authorWerner Almesberger <werner@almesberger.net>2016-07-01 12:48:23 (GMT)
committerWerner Almesberger <werner@almesberger.net>2016-07-01 12:48:23 (GMT)
commit1bc246012b0369cbe5d63d757ff100ced602f36e (patch)
tree72c2652fdd4cbdf8181b8b59579b1ab07655501d /ir
parent227db5d8855f29b5bb8fd266df5d016435357e3a (diff)
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ir/: update for more complete specs; lower photodiode speed estimate
- since we now know the number of configuration signals, "gpio(s)" can become "gpio" - we now know the receiver circuit specifications -> update diode characteristcs (this lowers the speed estimate from 2 MHz to 200 kHz) - various small typos and style corrections
Diffstat (limited to 'ir')
-rw-r--r--ir/cir.fig2
-rw-r--r--ir/ir.tex20
-rw-r--r--ir/irda.fig2
-rw-r--r--ir/sys.fig2
-rw-r--r--ir/uart.fig2
5 files changed, 15 insertions, 13 deletions
diff --git a/ir/cir.fig b/ir/cir.fig
index 237a890..d6ee480 100644
--- a/ir/cir.fig
+++ b/ir/cir.fig
@@ -77,8 +77,8 @@ Single
4 2 0 50 -1 22 12 0.0000 4 165 990 1080 2925 uart3_rts_sd\001
4 2 0 50 -1 22 12 0.0000 4 165 1125 1080 2610 uart3_cts_rctx\001
4 2 0 50 -1 22 12 0.0000 4 165 990 1080 2295 uart3_tx_irtx\001
-4 2 0 50 -1 22 12 0.0000 4 180 570 1080 1395 gpio(s)\001
4 1 0 50 -1 22 12 0.0000 4 135 570 1575 1260 control\001
4 1 0 50 -1 22 12 0.0000 4 135 1005 2925 5130 Audio codec\001
4 1 0 50 -1 22 12 0.0000 4 180 645 2700 1080 bq.GPIO\001
4 1 0 50 -1 22 12 0.0000 4 180 645 1800 4860 bq.GPIO\001
+4 2 0 50 -1 22 12 0.0000 4 180 450 1080 1395 gpios\001
diff --git a/ir/ir.tex b/ir/ir.tex
index 5e93a88..b580806 100644
--- a/ir/ir.tex
+++ b/ir/ir.tex
@@ -89,7 +89,7 @@ The IR subsystem supports both CIR and
IrDA operation. In CIR mode, it can receive incoming
IR signals and thus act as a ``learning'' remote control.
Furthermore, the IR transceiver can be configured to send and receive
-unmodulated data from the UART. We call this ``IR-UART'' mode
+unmodulated data from the UART. We call this ``IR-UART'' mode.
% CIR trumps IrDA
%
@@ -369,7 +369,7 @@ boot from (wired) UART even if the IR-UART configuration is selected.
The CPU can deactivate the transmitter and receiver, either both together
or one at a time,%
-\footnote{To be defined.}
+\footnote{See sections \ref{cfglogic} and \ref{irrx}.}
through the control signals to the IR subsystem.
When deactivated, the IR subsystem must draw as little current as possible.
@@ -516,14 +516,16 @@ Parameter & Requirement & Unit & Transmitter & Receiver \\
\hline
Wavelength & 850--950 & nm & 940 & 780--1050 \\
Beam angle & $\ge$ 50 & $\hbox to 0pt{}\degree$ & 50 & 150 \\
-Peak frequency & $\ge$ 0.3 & MHz & 23 & $\approx 2$ \\
+Peak frequency & $\ge$ 0.3 & MHz & 23 & $\approx 0.2$ \\
\end{tabular}
\end{tab}%
%
-Note that the peak frequency of 2 MHz for the receiver is an estimate
-based on the specified rise and fall times of 100 ns each, which are
-specified for a reverse voltage of 10 V whereas we would expect to
-operate at a lower voltage.
+Note that the peak frequency of 0.2~MHz for the receiver is an estimate
+based on the specified rise and fall times of 100~ns each, which are
+specified for a reverse voltage of 10~V and a load resistance of
+$\rm 1~k\Omega$ whereas we
+operate at 1.8~V and with a load of $\rm 22~k\Omega$. (See section
+\ref{irrx}.)
% Daylight filter
%
@@ -646,7 +648,7 @@ The transmitter circuit consists of the configuration
logic that chooses which signal to output depending on the
configuration requested by CPU and the bq.GPIO input,
the LED driver that amplifies
-the logic from the configuration logic, and finally the LED.
+the output of the configuration logic, and finally the LED.
\begin{center}
\includegraphics[scale=0.9,]{txcirc.pdf}
@@ -711,7 +713,7 @@ We drive the transmit LED through an n-FET in the current-limiting
configuration shown below.
The underlying concept is that the diode current flowing through R2
-raises the voltage at the source (S) of T1, until $\rm V_{GS}$
+raises the voltage at the source (S) of T1 until $\rm V_{GS}$
is at the level where the FET admits exactly the desired current.
\begin{center}
diff --git a/ir/irda.fig b/ir/irda.fig
index 77dfb99..4114538 100644
--- a/ir/irda.fig
+++ b/ir/irda.fig
@@ -77,7 +77,7 @@ Single
4 2 0 50 -1 22 12 0.0000 4 165 990 1080 2925 uart3_rts_sd\001
4 2 0 50 -1 22 12 0.0000 4 165 1125 1080 2610 uart3_cts_rctx\001
4 2 0 50 -1 22 12 0.0000 4 165 990 1080 2295 uart3_tx_irtx\001
-4 2 0 50 -1 22 12 0.0000 4 180 570 1080 1395 gpio(s)\001
+4 2 0 50 -1 22 12 0.0000 4 180 450 1080 1395 gpios\001
4 1 0 50 -1 22 12 0.0000 4 135 570 1575 1260 control\001
4 1 0 50 -1 22 12 0.0000 4 135 1005 2925 5130 Audio codec\001
4 1 0 50 -1 22 12 0.0000 4 180 645 2700 1080 bq.GPIO\001
diff --git a/ir/sys.fig b/ir/sys.fig
index 7a4e18c..35619e3 100644
--- a/ir/sys.fig
+++ b/ir/sys.fig
@@ -78,6 +78,6 @@ Single
4 2 0 50 -1 22 12 0.0000 4 165 990 1080 2925 uart3_rts_sd\001
4 2 0 50 -1 22 12 0.0000 4 165 1125 1080 2610 uart3_cts_rctx\001
4 2 0 50 -1 22 12 0.0000 4 165 990 1080 2295 uart3_tx_irtx\001
-4 2 0 50 -1 22 12 0.0000 4 180 570 1080 1395 gpio(s)\001
+4 2 0 50 -1 22 12 0.0000 4 180 450 1080 1395 gpios\001
4 1 0 50 -1 22 12 0.0000 4 135 570 1575 1260 control\001
4 1 0 50 -1 22 12 0.0000 4 135 1005 2925 5130 Audio codec\001
diff --git a/ir/uart.fig b/ir/uart.fig
index f1c710b..3e3bafe 100644
--- a/ir/uart.fig
+++ b/ir/uart.fig
@@ -77,8 +77,8 @@ Single
4 2 0 50 -1 22 12 0.0000 4 165 990 1080 2925 uart3_rts_sd\001
4 2 0 50 -1 22 12 0.0000 4 165 1125 1080 2610 uart3_cts_rctx\001
4 2 0 50 -1 22 12 0.0000 4 165 990 1080 2295 uart3_tx_irtx\001
-4 2 0 50 -1 22 12 0.0000 4 180 570 1080 1395 gpio(s)\001
4 1 0 50 -1 22 12 0.0000 4 135 570 1575 1260 control\001
4 1 0 50 -1 22 12 0.0000 4 135 1005 2925 5130 Audio codec\001
4 1 0 50 -1 22 12 0.0000 4 180 645 2700 855 bq.GPIO\001
4 1 0 50 -1 22 12 0.0000 4 180 645 1800 4860 bq.GPIO\001
+4 2 0 50 -1 22 12 0.0000 4 180 450 1080 1395 gpios\001