Boards Revisions FAQ and Errata

Introduction

Board FAQ

MCU Selection

Q: Which MCU should I use for my mcHF build?

A: One with at least 1MB flash, read below for more info.

You need a 100pin LQFP variant (the name is followed by T6, e.g. STM32F407VET6 ,STM32F439VGT6). All of the listed processors work, but if you have the choice, go for "Best" or at least "Good".

Name	Flash (kB)	RAM (kB)	Selection Comment
STM32F407VE	512	192	Not recommended, but works with small build
STM32F407VG	1024	192	OK, low RAM
STM32F405VG	1024	192	OK, low RAM
STM32F427VG	1024	256	Good
STM32F427VI	2048	256	Best, most flash and ram
STM32F429VG	1024	256	Good
STM32F429VI	2048	256	Best, most flash and ram
STM32F437VG	1024	256	Good
STM32F437VI	2048	256	Best, most flash and ram
STM32F439VG	1024	256	Good
STM32F439VI	2048	256	Best, most flash and ram

I2C EEPROM

Q: Which I2C EEPROM to use for my board?

A: All 24LC I2C EEPROMS work on all boards.

Some need modification, some are too small to be useful (memory size below 32kByte).

• 24LC1025 -> best choice for ver 0.6 boards, just solder in U7, other I2C EEPROM require pin 3 to be bent up and solder to pin 2 or pin 4 (i.e. GND).
• 24LC1026 -> best choice for ver 0.4 and 0.5 boards, just solder in U7. 24LC1025 needs pin3 to be bent, solder wire to pin8 (Vcc).

Q: Shall I fit an I2C EEPROM or not?

A: It is not required to have an I2C EEPROM solder in.

It is highly recommended, though. If not soldering in an I2C EEPROM you should as quickly as possible migrate to latest 2.0.x firmware, since older firmwares wear out flash much more quickly due to a programming mistake.

The reason why is that the EEPROM has a much higher write rate before failure (as in 1000 times more compared to the STM). The virtual EEPROM in the STM has never been designed to write that much (at every power off). Replacing an 8 pin EEPROM is easier than am STM.

RF Board

Q: I keep getting "Local Oscillator NOT detected" when I start the TRX

A:

• Your Si570 is not soldered correctly (happens often). Resolder and use a multimeter and the schematics to verify all pins connected correctly.
• Your Si570 is not the correct one. There are many different Si570 parts available. The chip marking is very important. It must be a CMOS output, 3.3V Si570 with the I2C address 0x55. If in doubt, you can enter your device number and check: Silabs Partnumber Lookup. The Si570 part number consists of "570" followed by the 3 letters and the 6 digit number in the second row, then the first letter in the 3rd row and finally the letter at the end of the 2nd row. To cut it short: The first letter and the third letter in the part number/ second marking row must be both "C"/, indicating a CMOS variant going up to 160 Mhz. The 6 digit number identifies the startup frequency AND the I2C address the Si570 uses. A working number is "000141", but all which identify a device with 0x55 as I2C address should work.

Revison 0.6

First read the change document provided by Chris, M0NKA: Changes from 0.5 to 0.6

EEPROM U7 Layout Change Breaks Compatbility With Most I2CEEPROMs

Layout was changed to directly support 24LC1025 (which requires Vcc at pin 3). This unfortunately breaks compatibility with many I2C EEPROMS especially with the 24LC1026.

Workaround: Except for the 1025 do not solder pin 3 (A2) to the pad on the pcb, but to the neighbor pin 2 (which is GND). See above in general section.

Revision 0.5

First read the change document provided by Chris, M0NKA: Changes from 0.4 to 0.5

Has its own page for now: FAQ-and-Errata-0.5-Boards