USBOpen(), USBSend() and USBRecv()

[matalog]

I have a HP Prime connected to a UMFT260EV1A, bought from Farnell:https://uk.farnell.com/ftdi/umft260ev1a/...derack-GLB

The HP Prime recognises it, when I enter USBOpen() it returns {{1027,24624}}.

I have JP7 connected at pins 2-3 and JP9 connected at pins 1-2. That is DCNF0 low and DCNF1 high.

That should set it to solely UART connection.

I have an FTDI232 device that I have set the 3.3V jumper on, and it is connected to my PC, then RealTerm - it is also connected to the RXD (TO TXD of FT260) and TXD (TO RXD of FT260) of the FT260.

If I enter USBOpen(1027,24624) it returns {64,64} as expected, but everytime I try USBSend(45) (for example) it returns "Error:Invalid Input".

USBRecv returns {}.

I have not changed the EEPROM in the FT260, and assumed that I would have been able to communicate with the calculator easier.

BTW, I have always been using Serial 19200 as I though nothing else would work.

The strangest thing though - If I follow the steps in this thread: https://www.hpmuseum.org/forum/thread-17848.html And perform :

Code:

EXPORT ft260_EEPROMrdall()  // TEST - dump ft260 ROM in L5 at once
BEGIN
LOCAL x, sts;
PRINT();
L5:={};
UClr();
ft260_open(); 
ft260_i2cSend(ft260,{0});       // start at reg 0
x:=256;
sts:=ft260_i2cReadReq(ft260,x); // read request #C2h, 256 bytes ...
IF TYPE(sts)=6 AND SIZE(sts)>0 THEN 
  L5:=SETBASE(R→B(sts),0);
END;
PRINT("I2C "+ STRING(L5));
UClose();
RETURN L5;
END;

Then the calculator actually returns the codes (numbers of ascii) that were transmitted from PC To Calculator.


Does anyone have any tips or ideas to help me ?