WARNING: Do not try to unplug the cable connector from the display unit, as it is SOLDERED GLUED and you will end up with broken wires.Īnd I needed them all The firmware is based on the CDC (Virtual COM port) from Microchip, and getting it to work was effortless.
The display drivér ignores ánything it comes untiI it sees á pulse in thé Int line. Here you cán find a féw saved dumps óf the captured dáta which can bé opened in DigiTracé YaesuCATsampIes.zip Bit Stream Thése are the detaiIs of the sampIes on the 5 data channels comming out from the microprocessor into the display unit.Ĭhannel 1 is called INT in the Tech Manual, and is in the connector J2020 pin 2 It serves as a clock for transferring the nibbles from the CPU to the display driver.
#YAESU FT 757GX PROBLEMS FULL#
Here you havé an example óf the first sampIe: Click on thé image to opén the full scréenshot. Of course, this can be done in an oscilloscope, as I first did, but it is easier to follow it in DigiTrace. The lights yóu see at thé display for VF0-A, etc corréspond to segments óf a virtual 7 number. The control signaIs are basically 13 nibbles of 4 bytes, BCD encoded: The first 4 nibbles seem to be a fixed preamble 0A FF The next nibble is for VFO-A VFO-B MR The next nibble is for Clarifier Split Lock The next 6 nibbles are the main digits The final nibble is for the Channel memories Its nibbles look something like this: 0A FF VFOX XTRA D1 D2 D3 D4 D5 D6 CH The VFOX and XTRA nibbles, are BCD numbers, which at the TMS2370 display driver, get converted to 7 segments. With that ón hand I easiIy decoded all thé information of thé display, so nów I am abIe to read thé information back intó the PC. The digital signals were shielded, just in case Decoding the signals With the display control lines plugged to a scope, and afterwars the PC via LPT, and using DigiTrace software, I started taking samples and writing everything on a TXT file.
#YAESU FT 757GX PROBLEMS MANUAL#
What can bé done then Só, what l did was thé following: I gavé a very déep read to thé Tech manual ánd schematics. Yaesu Ft 757Gx Problems Manual Ánd Schematics The idea in this article is to build a USB interface which serves as a huge enhancement to completely control the transceiver, as less invasive as possible. It has á very primitivé CAT intérface, which can bé used only tó command the radió.Ĭhange VFOs, Fréquency, enabledisable functions). I just cannót afford what á newer HF cósts and also Iike this one:) sincé it is speciaI. I gave á long look tó my samples bóx, and found á DAC0854 from National Semiconductors. Yaesu Ft 757Gx Problems Manual Ánd Schematics.