FTDI module interface to stamp queston

Diemaster

hi my first post i'd like to say hi

first let me apoligize for my spealing / grammer. never were good at them. THX GOD FOR SPEELCHECKS

i am by far no novice the basic stamp 2 was only a year old when i first got mine and have loved them ever since [noparse]:D[/noparse]

i got a FTDI USB module i installed on my breadbourd and eventualy in my project. it has TTL outputs (5 or 3.3)and i'm using 5.·so i'm running them to a MAX232 driver so i can program though USB. i'm doing it this way so i have TTL and 232 serial at my disposil.

this is the module i'm using: http://www.smileymicros.com/index.php?module=pagemaster&PAGE_user_op=view_page&PAGE_id=31&MMN_position=80:80

my question is:

A: can i use the ser gnd (pin #4) as a power ground?·
B: what is the ATN pin? TTL or 232? i would assume 232 since the serial port hooks up to it. can i get away with TTL?
C: are ALL the signals in a serial port 232 level or just the TXD/RXD?

Diemaster

no one knows anyting? i wana hook this up on my breadbourd to program and have a serial port.

allanlane5

1. Yes, you MUST use the "ser gnd" as a power ground.

2. I'm not sure about the ATN pin.

3. If you're talking about the BS2 "Programming" port, I believe all the signals are +-10 volt.

The problem is, there's several voltages that do "232 Level". It started out with +- 12 volts, then went to +- 10 volts (which is what the MAX2332 does) then went to +- 3 volts, and some chips do "232" signalling with zero and 5 volts.

Bottom line -- if the signal goes to the DB-9 connector on the BOE board, it's probably "232 level".

Diemaster

well i figured it out. using this schematic: http://www.parallax.com/Portals/0/Downloads/docs/prod/boards/BOE_USB_D_Schematic.pdf

i used the transistors in the middle of the page on my bread bourd and it works. i should it's the same FDIT chip or what ever it's called.