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Building the UI V1.8 Board
OVI40 UI V1.7 Documents
UI V1.7 documents are provided for information only. Please primarily use the V1.8 documents for building the UI V1.8 board.
Please note that the component placement docs are searchable pdf documents. During soldering they can be used to quickly find a component's location by entering the component reference (e.g. “R20”) in pdf search. No need to be concerned to use the V1.7 component placement doc for assembling a V1.8 UI board - V1.7 and V1.7 are quite similar in this respect.
OVI40 UI V1.8 Documents
OVI40 UI V1.8 Kit Contents
The kit contains UI V1.8 PCB, components in bags and packing list. The display is delivered as assembled and tested unit.
Assembly and Soldering
The graphics below - UI V1.7 with 3.2“ Display - give an impression on how the finished V1.8 UI board will look like:
Please read Errata carefully
Make sure to read the Errata carefully before starting assembly.
=== IC Device Markings ===
The smaller ICs can be identified by device mark. The following device marks are used:
Typ | Device Mark | Schematic | Purpose |
LP5907_Q1 | LLVB | IC3 | LDO 3.3 V |
BAV70 | A4 | D5, D6 | Diode |
BC857B | 3F | T3 | Transistor |
BAS85 | Ring = Cathode | D7 - D9 | Diode |
MCU STM32 "Pin 1" marking
Please understand the correct orientation of STM32 MCU Pin 1. There are two markings on the IC. Please not the text printed on MCU to find the correct Pin 1: When reading the text Pin 1 is on bottom left corner.
=== STM32F76X_ZIT vs. STM32H743ZIT6 ===
The kit is shipped with STM32F76X_ZIT (“F7”). The just released STM32H743ZIT6 (“H7”) may be used instead. It is suggested to use the F7 for now. Rwason: it is planned to support the H7 in the UHSDR, but no boot loader oder firmware is released for the H7 at the moment.
Comparison of MCUs:
mcHF: | OVI40: | OVI40 - future: | |
STM32F407VET6 | STM32F767ZIT6 | STM32H743ZIT6 | |
Flash[kB] | 500 | 2048 | 2048 |
RAM [kB] | 192 | 512 | 1024 |
Clock[MHz] | 168 | 216 | 400 |
FPU | single | double | double |
Pins | 100 | 144 | 144 |
DMIPS | 210 | 462 | 856 |
EEPROM IC7 orientation
This is where the dot is printed. Also the edge of the case is slanted near the 1-4 pins. See here
Do not solder in R101 for the EEPROM delivered with the kit (AT24CM02).
Prevent short cut with back up battery holder
One of the connection pins of the battery holder might touch ground connection of a rotary encoder. Make sure to cut this pin flush with PCB surface before soldering - see photo:
Polarised capacitors
Please observe mounting orientation of tantal and electrolytic capacitors. Markings on the capacitors are explained http://elektroniktutor.de/bauteilkunde/c_smdcod.html|here
Mounting locations of switches S7 and S8
Two different mounting locations are provided on the UI PCB for S7 and S8:
- “mcHF style”: S7 and S8 not line with switches under LCD - they are mounted slightly higher
- “OVI40 style”: S7 and S8 are mounted in line with the function keys under the LCD
“In line” is the preferred mounting location for S7 and S8.
IC9 und IC11: leave empty for now
IC9 (SPI FRAM) and IC11 (SPI FLASH) are for future use. Please leave empty for now. They are neither required nor supported by UHSDR at this time.
Modifications
Temporary Modification: Resistor in parallel to C94
Symptom: In stand-by the current drawn from back-up battery is excessively high. Work-around: Put resistor in parallel to C94. Start with a value of 56k - this seems to work in most cases. If board does not start increase value slightly. The same approach is used BTW in the commercially available Disco F746 prototype board.
Change brightness of LEDs
Helle LEDS: Mit den Bausatz-Vorwiderständen leuchten die LEDs sehr hell. DF9EH hat die Werte reduziert:
- R36 auf 22,6k (D1 grün)
- R37 auf 6,8k (D2 rot)
- R116 auf 6,8k (D3 blau)