tony_lth
Advanced Member level 5
Hi, ALL,
I designed a circuit, which can share RS422 and RS232 on the same pin.
Pls check the picture.
When "Control" is high, which has been pulled up to +5V.
IC400 Y =High, then U402 works properly, and U401 pin 13 F_TXD, i.e. RS232 TXD signal is converted to RS422 signals by U402. At the same time, U400 IN1 is "High", i.e. D1/S1 is OFF. So RS422_TXD+ pin is the TXD+ of RS422.
When "Control" is low, which should be linked to GND by GPIO, then U402 A/B are in high impedance, at the same time, U402 _RE is high, then U402 isn't in "receiver" status either.
But U400 D1/S1 is ON. So RS422_TXD+ pin is the TXD pin of RS232.
Finally, share the same pin for RS422 and RS232 signals.
Any comments?
Best,
Tony Liu
I designed a circuit, which can share RS422 and RS232 on the same pin.
Pls check the picture.
When "Control" is high, which has been pulled up to +5V.
IC400 Y =High, then U402 works properly, and U401 pin 13 F_TXD, i.e. RS232 TXD signal is converted to RS422 signals by U402. At the same time, U400 IN1 is "High", i.e. D1/S1 is OFF. So RS422_TXD+ pin is the TXD+ of RS422.
When "Control" is low, which should be linked to GND by GPIO, then U402 A/B are in high impedance, at the same time, U402 _RE is high, then U402 isn't in "receiver" status either.
But U400 D1/S1 is ON. So RS422_TXD+ pin is the TXD pin of RS232.
Finally, share the same pin for RS422 and RS232 signals.
Any comments?
Best,
Tony Liu