Replace the manual switch(jumper) with automatic switch(ic)

Question

I used rcm5600w interface board. Interface board used manual jumper to switch between download/debug and run programs.

Pins 1–2 on header JP1 on the Interface Board must be jumpered to download and debug applications. Pins 1–2 should be left unjumpered to run an program already loaded in flash memory.

I want to replace the manual switch with automatic switch, using ic switch MAX4514 or MAX4515. My question: Ic switch requires control pin to connect and disconnect switch. Which rcm5600w pin can be used to control the ic? Thank you.

Answer 1

Good afternoon, If I understand the question correctly you want to use an IC to control SMODE bit and you want to control this IC from RCM5600.
There is no easy way to do this because after reset all signals on Rabbit processor are set to their default state.

It is possible to connect SMODE to CBUS2 pin of FT232 and use that signal to control 5600.Please refer to FTDI documentation on how to do this.

Comments

@MargaretK, Thank You.  If I unjumpered pins 1-2 and then jumpered pins 3-4 on header JP1 on the Interface Board RCM5600W , this will connect CBUS2 pin of FT232 to pin 13 of the 74HC125 (pin 13 will be pulled up to 3.3v when download processing). I tried to download the program into the rabbit but failed.

Jumpered pins 3-4 is same logic with jumpered pins 1-2, the only difference is the source triger to pin 13 of the 74HC125 from Vcc (pins 1-2 jumpered) or CBUS2 pin of FT232 (pins 3-4 jumpered), but why i failed when download process?

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After I found the program to change the EEPROM value of FT232RL from http://www.ftdichip.com/Support/SoftwareExamples/CodeExamples/CSharp/EEPROM.zip.  I tried to change the value CBUS2 of FR232RL with all the options(cbus2=0x00 until cbus2=0x0C) but nothing worked.

The problems is how to set CBUS2 of FT232RL to high level while usb transmitte and receive data and also set to low level when usb idle mode.

All options as follows:

/// FT232R CBUS EEPROM options - Tx Data Enable
public const byte FT_CBUS_TXDEN = 0x00;

/// FT232R CBUS EEPROM options - Power On
public const byte FT_CBUS_PWRON = 0x01;

/// FT232R CBUS EEPROM options - Rx LED
public const byte FT_CBUS_RXLED = 0x02;

/// FT232R CBUS EEPROM options - Tx LED
public const byte FT_CBUS_TXLED = 0x03;

/// FT232R CBUS EEPROM options - Tx and Rx LED
public const byte FT_CBUS_TXRXLED = 0x04;

/// FT232R CBUS EEPROM options - Sleep
public const byte FT_CBUS_SLEEP = 0x05;

/// FT232R CBUS EEPROM options - 48MHz clock
public const byte FT_CBUS_CLK48 = 0x06;

/// FT232R CBUS EEPROM options - 24MHz clock
public const byte FT_CBUS_CLK24 = 0x07;

/// FT232R CBUS EEPROM options - 12MHz clock
public const byte FT_CBUS_CLK12 = 0x08;

/// FT232R CBUS EEPROM options - 6MHz clock
public const byte FT_CBUS_CLK6 = 0x09;

/// FT232R CBUS EEPROM options - IO mode
public const byte FT_CBUS_IOMODE = 0x0A;

/// FT232R CBUS EEPROM options - Bit-bang write strobe
public const byte FT_CBUS_BITBANG_WR = 0x0B;

/// FT232R CBUS EEPROM options - Bit-bang read strobe
public const byte FT_CBUS_BITBANG_RD = 0x0C;