Hi,

sure I can:

Serial.println("Waking up EVE chip");
// Wake-up FT81x
ft81xPowerDown(); // 1) lower PD#
delay(300); // 2) hold for 20ms
ft81xPowerUp(); // 3) raise PD#
delay(300); // 4) wait for another 20ms before sending any commands
ft81xCmdWrite(FT81x_RST_PULSE);
delay(300);

ft81xCmdWrite(FT81x_CLKINT); //send command "CLKEXT" to use the external clock source
//ft81xCmdParamWrite(FT81x_CLKSEL, 0x00); //select the system clock frequency => default 60 Mhz
ft81xCmdWrite(FT81x_ACTIVE); //send host command "ACTIVE" to wake up
SPI_TO_EVE_FAST;
delay(500); // Give some time to process

// --------------- Check that FT8xx ready and SPI comms OK -----------------
unsigned char regId = ft81xMemRead8(REG_ID);
while (regId != 0x7C)                                        // Read REG_ID register (0x302000) until reads 0x7C
{
Serial.println("Reading EVE REG_ID...failed");
delay(500);
}
Serial.print("EVE REG_ID = ");
Serial.println(regId, HEX);
delay(100);

This seems to be the standard init i found somewhere...
First reset is a hardware reset via /PD, the line below it is an additional SW reset just for trying it but seems to make no difference.
When i put in FT81x_CLKINT the chip starts working (pulsing, answering register reads and so on) with CLKEXT it hangs in the "// Read REG_ID register (0x302000) until reads 0x7C" loop forever...
I also tried with lower SPI speeds without success.

So in general, is there an external crystal needed ? Are there limitations if there is no crytal and i rely only on the internal clocking ?
Is there a crystal type you recommend ? Perhaps i have the wrong one...it is 12 Mhz, are 18 pF the right Cs ?, for the crystal it says it has 20pF 70Ohms...connections on the PCB to the BT818 are short (approx 2...4 mm) i am not the hardware expert here...for oscillating circuits...

Thank you

Torsten

Hi,

thank you for your quick response....i disconnected the ST7701 from the BT81x and level is still low....so i assume the device is damaged...will try with a new one...

Thank you

Torsten