终端输入串行命令，输出Arduino Tx

Question

I am somewhat of a beginner in this space

I am using Arduino Mega2560 and interfacing it with a coin machine from a vending machine. The coin machine runs on a protocol called MDB (multi-drop bus) which is 9bit serial. I would normally use the Arduino IDE but that does not cater for 9-bit serial. I have therefore decided to code using c and ubuntu 12.04. I have come across a usart setup function which can bitbash into 9bit mode. I have installed avr-gcc avr-libc avrdude.

The coin machine acts depending on serial data it recieves. ie to reset it needs to read 100101010 from its Rx (this is a random 9-bit number, I am not sure what the true number is at this moment). Another example would be if it recieves 10101111 on Rx it would dispense a coin of desired type etc. There are also various other commands like ack,poll, etc. So what I want to do is send the appropriate binary numbers out from the Arduino's Tx and into the coin machine's Rx and try get communication with the coin machine.

This was just for context but my main question is more general (lets assume we are working in 8bit mode):

a) how can I type a 8bit binary number (eg 10111010) on the terminal, and have that number be put on the Tx line of the arduno. b) since the mega2560 has 3 Tx/Rx modules, can I Tx from one module and Rx from another module, for testing, such that the 8bit binary number I type in terminal appears on the terminal too.

note: The reason I want the numbers to be represented in binary is because I want to see each bit, it will make more sense to me that way

I am trying to do something similar to Bouni's MateDealer (see github repository) but he is implementing the Arduino as a slave, I want to implement as a master. More on his project here .

Thank you kindly!

Answer 1

A) There is two solutions:

• you send the binary representation of the number, like '00001111' through the serial line, and then in the µC you use the function strtoul, which takes as parameters an array of char (in this case '00001111') and the base (here 2) and returns the corresponding value (here 0x0F, or 16);
• you create your own terminal, which converts the input binary representations into decimal representations (here, converts '00001111' into '16'), sends to the µc which uses the function atoi to get the corresponding value (here, 16 or 0x0F)

I think that the former will be easier, but a little bit slower, while the latter could offload the microcontroller.