From 2a5066ac5fb6acfe7b894a91f5e87a93e0bf8b71 Mon Sep 17 00:00:00 2001
From: occheung <dc@m-labs.hk>
Date: Tue, 7 Jun 2022 13:49:14 +0800
Subject: [PATCH] 2118-2128: add <8ns short pulse example

---
 2118-2128.tex   | 11 ++++++++++-
 examples/ttl.py | 12 ++++++++++++
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/2118-2128.tex b/2118-2128.tex
index beebe51..17fe27a 100644
--- a/2118-2128.tex
+++ b/2118-2128.tex
@@ -508,10 +508,19 @@ The channel should be configured as output in both the gateware and hardware.
 
 \newpage
 
+\subsection{Sub-coarse-RTIO-cycle pulse}
+With the use of the ARTIQ RTIO, only 1 event can be enqueued per coarse RTIO cycle, which is typically 8ns.
+Therefore, to emit a pulse that is less than 8ns, additional delay is needed such that the \texttt{ttl.on()} \& \texttt{ttl.off()} event are submitted at different coarse RTIO cycles.
+The TTL pulse parameter must satisfy the minimum pulse width stated in the electircal specifications.
+
+\inputcolorboxminted{firstline=88,lastline=92}{examples/ttl.py}
+
 \subsection{Morse code}
 This example demonstrates some basic algorithmic features of the ARTIQ-Python language.
 \inputcolorboxminted{firstline=22,lastline=39}{examples/ttl.py}
 
+\newpage
+
 \subsection{Counting rising edges in a 1ms window}
 The channel should be configured as input in both the gateware and hardware.
 \inputcolorboxminted{firstline=47,lastline=52}{examples/ttl.py}
@@ -520,7 +529,7 @@ This example code uses the software counter, which has a maximum count rate of a
 If the gateware counter is enabled on the TTL channel, it can typically count up to 125 million events per second:
 \inputcolorboxminted{firstline=60,lastline=65}{examples/ttl.py}
 
-\newpage
+To count falling edges or both rising \& falling edges, use \texttt{gate\char`_falling()} or \texttt{gate\char`_both()}.
 
 \subsection{Responding to an external trigger}
 One channel needs to be configured as input, and the other as output.
diff --git a/examples/ttl.py b/examples/ttl.py
index b98603e..7c38c80 100644
--- a/examples/ttl.py
+++ b/examples/ttl.py
@@ -78,3 +78,15 @@ class ExternalTrigger(EnvExperiment):
         timestamp_mu = self.ttlin.timestamp_mu(gate_end_mu)
         at_mu(timestamp_mu + self.core.seconds_to_mu(10*ms))
         self.ttlout.pulse(1*us)
+
+
+class ShortPulse(EnvExperiment):
+    def build(self):
+        self.setattr_device("core")
+        self.ttl0 = self.get_device("ttl0")
+    
+    @kernel
+    def run(self):
+        self.core.reset()
+        delay(6*ns)
+        self.ttl0.pulse(3*ns)