From d0b21a8e85f75ae1db85c5c889f4d7250143abd8 Mon Sep 17 00:00:00 2001
From: Sebastien Bourdeauducq <sb@m-labs.hk>
Date: Thu, 20 Jul 2017 12:01:29 +0800
Subject: [PATCH] manual: add short description of drivers, with replace
 support information. Closes #777

---
 artiq/coredevice/ad5360.py |  8 ++++++++
 artiq/coredevice/dds.py    |  8 ++++++++
 artiq/coredevice/i2c.py    |  5 +++++
 artiq/coredevice/sawg.py   | 10 ++++++++++
 artiq/coredevice/spi.py    |  8 ++++++++
 artiq/coredevice/ttl.py    |  8 ++++++++
 6 files changed, 47 insertions(+)

diff --git a/artiq/coredevice/ad5360.py b/artiq/coredevice/ad5360.py
index 3338db4ab..c470fbec2 100644
--- a/artiq/coredevice/ad5360.py
+++ b/artiq/coredevice/ad5360.py
@@ -1,3 +1,11 @@
+"""
+Driver for the AD5360 DAC on RTIO.
+
+Output event replacement is not supported and issuing commands at the same
+time is an error.
+"""
+
+
 from artiq.language.core import (kernel, portable, delay_mu, delay)
 from artiq.language.units import ns, us
 from artiq.coredevice import spi
diff --git a/artiq/coredevice/dds.py b/artiq/coredevice/dds.py
index a6d9c2dd1..5c7293edf 100644
--- a/artiq/coredevice/dds.py
+++ b/artiq/coredevice/dds.py
@@ -1,3 +1,11 @@
+"""
+Drivers for direct digital synthesis (DDS) chips on RTIO.
+
+Output event replacement is not supported and issuing commands at the same
+time is an error.
+"""
+
+
 from artiq.language.core import *
 from artiq.language.types import *
 from artiq.language.units import *
diff --git a/artiq/coredevice/i2c.py b/artiq/coredevice/i2c.py
index ce8ca33ea..92d66b8dd 100644
--- a/artiq/coredevice/i2c.py
+++ b/artiq/coredevice/i2c.py
@@ -1,3 +1,8 @@
+"""
+Non-realtime drivers for I2C chips on the core device.
+"""
+
+
 from artiq.language.core import syscall, kernel
 from artiq.language.types import TBool, TInt32, TNone
 from artiq.coredevice.exceptions import I2CError
diff --git a/artiq/coredevice/sawg.py b/artiq/coredevice/sawg.py
index d455db28e..be4854820 100644
--- a/artiq/coredevice/sawg.py
+++ b/artiq/coredevice/sawg.py
@@ -1,3 +1,13 @@
+"""
+Driver for the Smart Arbitrary Waveform Generator (SAWG) on RTIO.
+
+The SAWG is an "improved DDS" built in gateware and interfacing to
+high-speed DACs.
+
+Output event replacement is supported except on the configuration channel.
+"""
+
+
 from artiq.language.types import TInt32, TFloat
 from numpy import int32, int64
 from artiq.language.core import kernel, now_mu
diff --git a/artiq/coredevice/spi.py b/artiq/coredevice/spi.py
index c5422f11c..9069a40d6 100644
--- a/artiq/coredevice/spi.py
+++ b/artiq/coredevice/spi.py
@@ -1,3 +1,11 @@
+"""
+Driver for generic SPI on RTIO.
+
+Output event replacement is not supported and issuing commands at the same
+time is an error.
+"""
+
+
 import numpy
 
 from artiq.language.core import syscall, kernel, portable, now_mu, delay_mu
diff --git a/artiq/coredevice/ttl.py b/artiq/coredevice/ttl.py
index efa96cba2..76b443eb7 100644
--- a/artiq/coredevice/ttl.py
+++ b/artiq/coredevice/ttl.py
@@ -1,3 +1,11 @@
+"""
+Drivers for TTL signals on RTIO.
+
+TTL channels (including the clock generator) all support output event
+replacement. For example, pulses of "zero" length (e.g. ``on()``
+immediately followed by ``off()``, without a delay) are suppressed.
+"""
+
 import numpy
 
 from artiq.language.core import *