docs: add tutorial for using suzyq

BUG=b:140551928
BRANCH=none
TEST=read doc.

Change-Id: I1032433de1f8284cffff1e12e906d3fffd5ae32a
Signed-off-by: Mary Ruthven <mruthven@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/1816871
Reviewed-by: Wai-Hong Tam <waihong@google.com>

1 files changed, 69 insertions, 0 deletions

diff --git a/docs/ccd_howtos.md b/docs/ccd_howtos.md
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+# CCD How-tos
+This doc contains tutorials for using CCD. These tutorials only cover using GSC
+CCD. Some use cases will be very similar to using CCD from ryu, servo micro, or
+servo v4, but these guides are not guaranteed to work for them. More detailed
+instructions on how to use different parts of CCD are in the
+[GSC CCD doc](case_closed_debugging_cr50.md).
+
+[TOC]
+
+---
+## How to Use SuzyQ
+This goes through the steps to connect SuzyQ and start using CCD.
+
+### Requirements
+
+*   A [SuzyQ]. If you don't have one, they're sold at [sparkfun]
+*   A ChromeOS device that supports CCD.
+
+### Steps
+
+1.  **Charge your chromebook.** Suzyq can't charge your device. If it's not
+    charged, the device may run out of power while debugging.
+
+2.  **Connect the type A side of Suzyq to your workstation.**
+
+3.  **Connect the type C part of your Suzyq to your chromebook.**
+
+4.  **Verify the CCD device exists.**
+
+    *   **Look for a device with the right vid:pid.** Cr50 vid:pid is 18d1:5014.
+        You can use lsusb to check that it shows up.
+
+                > lsusb -vd 18d1:5014
+
+    *   **Debug connection issues**. If the device doesn't show up, disconnect
+        suzyq from the DUT and either flip it or plug it into the other port. If
+        your device has 2 type c ports, there are 4 ways to connect suzyq. Only
+        one works.
+
+        *   **Port:** The DUT only supports CCD on one type C port. Try the
+            other port if CCD doesn't show up.
+
+        *   **Orientation:** Suzyq is orientation dependent, so it may be on the
+            correct port, but it needs to be flipped.
+
+5.  **Check basic CCD functionality**. After the CCD device shows up, the cr50, ec,
+    and ap consoles should show up in /dev/ttyUSB\*
+
+    *   Search for console names.
+
+                > ls /dev/ttyUSB*
+
+    *   If you run the `ls` command before and after connecting suzyq, then the
+        new devices should be the CCD consoles. The consoles are ordered. Cr50
+        should be the lowest ttyUSB device, then AP, and EC should have the
+        highest number. Running `ver` on all of them could also let you know
+        which one is which if you don't want to remember the order.
+
+    *   Open the console.
+
+                > minicom -D /dev/ttyUSB0
+
+    *   AP and EC consoles may be read-only depending on the CCD state. See the
+        [Setup CCD] instructions to enable them. Being able to use the cr50
+        console is a good enough sign that your Suzyq setup is ok.
+
+[Setup CCD]: ./case_closed_debugging_cr50.md#CCD-Setup
+[sparkfun]: https://www.sparkfun.com/products/14746
+[SuzyQ]: https://chromium.googlesource.com/chromiumos/third_party/hdctools/+/refs/heads/master/docs/ccd.md#suzyq-suzyqable