What are the RSF3 extras? What the big screen do?

Ez már működik stabilan?

Ráérsz majd béta tesztelni?

Do you have time for beta testing?

Turbo EXDOS option also tested:

6MHz and less... anti-turbo testing

 

This is just a first test of the Si5351A programable Clock generator module. It can be programmed via I2C bus, so a microcontroller is needed, which executes the task.
ESP8266 hacked to work as Arduino, then it just works as a simple microcontroller not as wifi.

The Si5351 has 3 independent clock outputs. The plan: one for the internal System bus (CPU), one for external System bus (Turbo EXDOS), and optionally the third to replace Nick complicated clock generator (broken L2 and can't get replacement problem).

Welcome here!

This is screen: uninitialised Nick chip display power on garbage of video RAM.
It is means the system freeze before the ROM enter to the display initialisation phase.

Most possible problems:
-dead RAM chip. The original EXOS ROM have a bug: put the stack pointer to untested RAM, and if onboard memory faulty can't report the fault because using CALLs, which are never return.
For this situation I wrote small test, what I also recommended to others.
-faulty Z80. Already found some, all are Zilog type, made in Phillipines serie. Some are really crazy: can execute program, but when write to RAM one or more bits are faulty.
-defective Dave chip. One or more outputs are dead. If the /ROM signal dead can be replaced with few 74 series chip.