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Hello, Grateful if any one could point me to a chip that will do TTL to RS232 wihout inversion. Thanks |
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TTL to RS232 conversion without inversion
Started by ●November 7, 2003
Reply by ●November 7, 20032003-11-07
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For example, the well-known MAX232, uses five external capacitors, and
will convert your BX's TTL to standard RS-232 voltage levels, doing all required inversion. To explain it simply, if you connect one of these between your PC's serial port and your BasicX, the two will be able to talk without any trouble at all. The MAX232 has two bidirectional channels, which means it can cope with two TX/RX serial ports. If you don't want to have to use the five capacitors and can afford the cost, you can use the MAX233, which simply needs 5V and three jumpers between pins. Regards, Mike ----- Original Message ----- From: "iclsidsan" <> To: <> Sent: Friday, November 07, 2003 11:27 AM Subject: [BasicX] TTL to RS232 conversion without inversion > Hello, > > Grateful if any one could point me to a chip that will do TTL to > RS232 wihout inversion. > > Thanks > ">http://docs.yahoo.com/info/terms/ |
Reply by ●November 7, 20032003-11-07
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I don't know of any such chip and would opine that there is none. The RS-232 standard defines "mark" and "space" (i.e. 1 and 0) levels that are logically inverted so this is the "natural" state. If you insist on having RS-232 levels that are backward from the standard, it is a simple matter to put an inverter between the BX-24 and the MAX232 chip. If you don't want to add a package with unused gates, an ordinary transistor and two resistors will do the job as well. Don in Portland, OR --- In , "iclsidsan" <it-and-RD@i...> wrote: > Hello, > > Grateful if any one could point me to a chip that will do TTL to > RS232 wihout inversion. > > Thanks |
Reply by ●November 15, 20032003-11-15
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--- In , "iclsidsan" <it-and-RD@i...> wrote: > Hello, > > Grateful if any one could point me to a chip that will do TTL to > RS232 wihout inversion. > > Thanks Hello, Actually, you don't need such chip. You can use MAX232 or something like this. Just use two inverters in series to get noninverting gate with RS-232 input and RS-232 output. If you use MAX232, you can get two such gates: first gate: input pin 13, output pin 14 (pin 12 connected to pin11); second gate: input pin 8, output pin 7 (pin 9 connected to pin10). Now put one gate between PC COM-port pin 2 and BX-24 pin 1 (use right direction of the gate ;-). And you can put second gate between PC COM-port pin 3 and BX-24 pin 2 (actually you also can connect both pins directly to each other without noninverting gate). Second, if your power supply is 7.5 12 volt you may use MAX231. Use this voltage to supply high voltage pin of MAX231 (pin 14 in DIP- package). In conclusion, if you use hyperterminal you have to set in "Port Setting": "Flow Control" as "None". Good, luck Alex |
