VK3KYY wrote: ↑Tue Feb 14, 2023 3:35 am
I think the UV380 has multiple GPIO's which need to be enabled when transmitting, or receiving, but we don't know why
Good. The more I investigate this hardware, the more I'm sure it's in some kind of middle ground between the GD77 and the MD-UV3x0. It uses the same rotary and a similar amp section to the latter, and also an identical battery pack, but inside it has the MK22 MCU.
In fact, there was a previous version to this radio (the MD-680) that was non-waterproof and had a slightly smaller battery. More or less what happens between the MD-UV380 and 390.
Anyway, I just bought a couple
AT24C512 and
W25Q64 modules (originally intended for arduino, so it'll be easier to solder them rather than a small chip) and as soon as I receive them I'll solder them and that'll make waaaay easier the coding part. It makes much more sense than storing the codepug in hard-coded variables, as that'll enable the radio to be programed via the CPS, have voice prompts, etc.
The only thing I have to check is whether the 25Q64 can be connected via SPI to the ports C0, C3, C5, C6 and C14, which are the ones that are wired to the terminals on the side. But I believe that won't be problematic. The AT24C512 can be easily connected in parallel to the AES chip I2C pins.
I'll also be receiving an ATGM336H UART GPS chip, which I'll wire to the UART terminals at the bottom of the PCB (and the ON/OFF pin to whatever GPIO pin I can find available). As the UART and USB pins of the MK22 are connected together in this radio, I'll have to make sure the GPS module is off before connecting the usb to a computer, so they don't interfere with each other.
This is starting to look really promising. It could mean that only with a slight hardware modification (
just adding the flash and eeprom, way easier than the mods you have to do to have M17 with the OpenRTX firmware, which in my opinion are too hard just for an experimental mode) the radio could be fully compatible with OpenGD77. So
this could be useful not only to me, but to anyone willing to make this mod to the radio and flash the firmware via SWD.
Thank you so much, I will be posting my findings here as soon as I get everything.