From: Bdale Garbee <bdale@gag.com>
Date: Sat, 19 Sep 2020 04:55:29 +0000 (-0600)
Subject: create a ToDo file to document work needed on Altus Metrum products
X-Git-Tag: telelco-v3.0~308
X-Git-Url: https://git.gag.com/?a=commitdiff_plain;h=0a8b5c55cf0769e475717d8b5f37d84f20914150;p=hw%2Faltusmetrum

create a ToDo file to document work needed on Altus Metrum products
---

diff --git a/ToDo b/ToDo
new file mode 100644
index 0000000..3ba12cc
--- /dev/null
+++ b/ToDo
@@ -0,0 +1,23 @@
+- rationalize LED current limiting resistors to use 1k everywhere except
+  TeleLaunch products using high-intensity, sunlight-readable LEDs that need
+  different values
+
+- switch all 32 MHz and 40 MHz crystals to a 2.0x1.6 mm packages, using a 
+  footprint that has the outside dimentions of the ECX-1637B and inter-pad 
+  spacings from the Murata XRCGB40M000F1S1LR0 to ensure we can change crystals 
+  over time if needed.
+
+  - switch all STM32 based products to 32 MHz crystals for the SOC except
+    TeleDongle, which could move to an STM32F042 and sync to USB with no 
+    crystal.  Absolute crystal specs aren't very important here, but it's 
+    hard not to spend a fracton of a cent more for parts Bdale likes...
+
+	best choice:		DK 490-14308-2-ND
+
+  - switch all CC1200 based products to 40 MHz crystal in 2.0x1.6 mm package,
+    with the possible exception of TeleMini/TeleMicro if that's just too hard.
+    We care about frequency accuracy and stability for these.
+
+	cheapest credible:	DK XC3069TR-ND
+	currently available:	DK 490-XRCGB40M000F1S1LR0TR-ND
+