README: develop assembly and test plan

1 files changed, 69 insertions, 4 deletions

diff --git a/README.md b/README.md
index 61c408e..440d5a8 100644
--- a/README.md
+++ b/README.md
@@ -8,8 +8,73 @@ combined with the [Anglian 3L transverter](http://www.g4ddk.com/Products.html).
 * Meant to be used with a microwave transverter
   * But also stand-alone 28MHz and 144MHz (The IF bands)
 * Using an ATMega controller
-  * Si5351 clock source
+  * Si5351 clock source (generates 3 clocks)
   * An LCD display
-* Maybe
-  * Includes the Lars Widenius GPSDO originally published on [eevblog](https://www.eevblog.com/forum/projects/lars-diy-gpsdo-with-arduino-and-1ns-resolution-tic/?all)
-  * Offers a 10MHz output refclk for a transverter
+* Discarded ideas
+  * Include a Lars Widenius GPSDO originally published on [eevblog](https://www.eevblog.com/forum/projects/lars-diy-gpsdo-with-arduino-and-1ns-resolution-tic/?all)
+  * Offer a 10MHz output refclk for a transverter
+  * Instead, have a 25MHz ref input, and use a LeoBodnar reference
+
+TODO before ordering the PCB
+============================
+
+* Switching
+  * Check switching with ATmega and validate resistors
+
+* Microphone input
+  * Verify microphone pinout for MH-42
+  * Is audio level at SSM2167 output sufficient for the SA602A ?
+
+* Audio out
+  * Change RV303 footprint, as it needs to be on the front panel
+
+* CW
+  * Does the trick with the DC bias to leak the LO work ?
+
+* Consider reordering UI pins, if it simplifies routing
+  * Mockup location of potentiometers, encoder, display and buttons
+  * Check cabling
+
+* Si5153
+  * Check desired frequencies can be achieved:
+    * LO1 = 28 - 4.9152 + VFO
+    * BFO = 4.91521
+    * VHF-LO = 144 + 28 and 144 - 28
+
+PCB Assembly Plan
+=================
+
+1. DCDC converter for 8V and LDOs
+  * Check output voltages
+  * Check drop under load
+
+2. ATmega
+  * Programming
+  * Sidetone low-pass
+  * Probably need to do a UI proto already
+
+3. Si5153
+  * Check I2C works
+
+4. 8V and 5V relay
+
+5. Baseband
+  1. Crystal filter shape
+  2. RX and TX filter shape
+  3. Receive path: IF mixer, crystal filter relay, IF AGC, BFO mixer, AGC measure, AF amp, SPKR
+    * Verify LO levels into SA602A: at least 200mVpp
+  4. Transmit path: Mic amp
+
+6. Anglian
+  1. LO filter shape
+  2. LO amp. Mixer needs +7dBm
+  3. All passives
+    * Verify correct voltages for amplifiers
+    * Verify PIN currents (Between 20mA and 60mA, below 0.8V)
+    * Verify filter shapes
+  4. IF amplifiers, both RX and TX
+  5. VHF amplifiers
+  6. VHF bandpass filter
+  7. Mixer
+
+7. External switching relay