I have a circuit that uses only a ATtiny2313 and a MAX232N. Basically what the circuit is supposed to do is Start and stop a timer based on two switches and reset the timer with a third switch. The program then calculates speed and prints it to Hyperterminal.
Everything is working great except I cant send commands to the ATtiny2313
Turn the Power On
Hit the reset switch to ready the counter (or hit "R" from HyperTerm)
Hit the start Switch to start the counter
Hit the stop Switch to stop the counter
...The ATtiny2313 then calculates the speed and spits it out like it should.
However... When I press the "R" key on my keyboard to reset the timer it does not work and I cant figure out why. The chips transmit the data just fine but wont receive it.
My first question is how to I look at the signal with a scope?
From my trial I connected the scope ground to ground and the scope positive to pins 7 and 8 of the MAX232.
Pin 7 (Rx) = 8Vdc
Pin 8 (Tx) = 10Vdc
Pin 9 (MAX232) is connected to Pin 2 (ATtiny2313)
Pin 10 (MAX232) is connected to Pin 3 (ATtiny2313)
I am using 1uf Caps on pins 4 to 5, 1 to 3, 2 to +5v, and 6 to grnd of the MAX232.
I was thinking that there may be a bit not set right in my program but a friend of mine built what we think is the same circuit and he is able to receive data. He is using SIM boards from dontronics for most of his circuit which arepre built whereas I am doing everything from scratch with wire and protoboards.
Please help!
Everything is working great except I cant send commands to the ATtiny2313
Turn the Power On
Hit the reset switch to ready the counter (or hit "R" from HyperTerm)
Hit the start Switch to start the counter
Hit the stop Switch to stop the counter
...The ATtiny2313 then calculates the speed and spits it out like it should.
However... When I press the "R" key on my keyboard to reset the timer it does not work and I cant figure out why. The chips transmit the data just fine but wont receive it.
My first question is how to I look at the signal with a scope?
From my trial I connected the scope ground to ground and the scope positive to pins 7 and 8 of the MAX232.
Pin 7 (Rx) = 8Vdc
Pin 8 (Tx) = 10Vdc
Pin 9 (MAX232) is connected to Pin 2 (ATtiny2313)
Pin 10 (MAX232) is connected to Pin 3 (ATtiny2313)
I am using 1uf Caps on pins 4 to 5, 1 to 3, 2 to +5v, and 6 to grnd of the MAX232.
I was thinking that there may be a bit not set right in my program but a friend of mine built what we think is the same circuit and he is able to receive data. He is using SIM boards from dontronics for most of his circuit which arepre built whereas I am doing everything from scratch with wire and protoboards.
Please help!