Post by thread:M-bus master

Hello people, i want your opinion in this problem of mine. I need to convert the variation of current in a line to data bits (it's the way the M-Bus works). The current in the bus is Ii (grafic below), this is the idle current (might change a little), when a slave drives the bus the current will rise to Io (the difference is known). . / \ | | Io | ---- ---- | | | | | Ii |---- ----- ----- | --------------------------> t I want to use the built in UART so i think it's ok to use something like this: | ------------ | | | . |----- | PIC16C73 | / \ - | | | | | | |__|\ | | I | | | R | \______| AN0 | | | | __| / | | - | |/ | | | | | | |----- | | | ---| | | | | | | | | | | -->| RX | | | ------------ The ISR will work like a debounce routine and then outputs the value that will be read by the UART (i think this is easier them doing that by software). This is part of my hack of a master M-Bus transceiver, the rest is still growing in my mind. Any help... comments... ideas ?..

At 12:20 16/05/97 +0000, Antonio Almeida wrote: >The ISR will work like a debounce routine and then outputs the value that >will be read by the UART (i think this is easier them doing that by >software). I'd try to "debounce" the comparator output properly in hardware (right switching point, right hysteresis), then you should be able to go directly into the UART.