I’ve been fussing with this issue fro a while now, and i am at a loss. i recently purchased a pro mini (the one with off-board USB) and am trying to program it. now, i do not have the FTDI breakout board or cable, as i thought i could use my setup.
I was intending on programming my pro mini via rs232. from what i’ve read, you cant just take rs232 level signals into the pro mini, they must be TTL. so i dug up one of my rs232 to TTL chips, Its a MAX233. i hooked it up, and after countless combinations of wire switching, i still cant get the arduino software to upload my sketch. i am using my laptop’s built in serial port. not one of those cheap usb to rs232 adapters.
Heres the configuration i thought was the most likely to work, but didnt.
With the MAX233 chip in my serial port, i provided the chip’s Vcc with +5 and ground. the TXd of the CHIP i put on the pro mini’s RX1, and the RXd of the MAX233 chip to the pro mini’s TX0.
now i know the MAX233 does not bring out the DTR for the automatic reset, so i brought that right off the serial port to the reset line.
When i hit upload, it compiles, thenit tries to upload to the I/O board. the board resets (i see the LED blink) but then it just times out. ive tried manual reset, ive tried close to everything!
Is this not possible? MUST i purchase a FTDI board or cable? from what i can tell, the FTDI also uses TTL. i dont understand why my configuration is failing.
Any help is greatly appriciated! thanks!