I'm a real beginner in micro controller so I basically have no idea what I'm doing and just do things base on the documents I read.
Basically I'm trying to communicate on a device with its own protocol but the data transmitted is a 16bits uart rx and tx is sent by turn.
this is a 3 pin connection. Pico is acting as slave.
pin1 signals the start of transfer: Low start, High end
pin2 determines who is sending the data: High master is sending, Low slave is sending
pin3 is the data pin: 18 bits is transmitted by master and slave in turn, includes start bit, data and end bit
Baud rate is 115200 (I get inconsistent data when using this in divider that's why I don't use it)
I have no problem reading the data but I can't seem to send data. I used another one of my pico to analyze the data but I only see data sent by master. How do I switch the pin's direction properly to transmit data to the master device?
Basically I'm trying to communicate on a device with its own protocol but the data transmitted is a 16bits uart rx and tx is sent by turn.
this is a 3 pin connection. Pico is acting as slave.
pin1 signals the start of transfer: Low start, High end
pin2 determines who is sending the data: High master is sending, Low slave is sending
pin3 is the data pin: 18 bits is transmitted by master and slave in turn, includes start bit, data and end bit
Baud rate is 115200 (I get inconsistent data when using this in divider that's why I don't use it)
I have no problem reading the data but I can't seem to send data. I used another one of my pico to analyze the data but I only see data sent by master. How do I switch the pin's direction properly to transmit data to the master device?
Code:
.program gbacom.define public SC_PIN 1.define public SO_PIN 2.wrap_target; Start receiving data wait 0 gpio SC_PIN ;wait start of transmission wait 1 gpio SO_PIN ;wait signal master transmitting set pindirs, 0 ;set pin input wait 0 pin 0 [4] ;[start bit] set x, 31 [28]start_bit:nop [30] ;just to skip start bitjmp x-- start_bit ;start bit end set y, 15 ;read 16 bitsloop_bit: in pins, 1 [5] ;read 1 bit set x, 31 [30]loop_inner: nop [31] jmp x--loop_inner jmp y--loop_bit push wait 0 gpio SO_PIN ;wait signal for slave to transmit pull wait 0 pin 0 [4] ; set pindirs, 1 ;set pin out set y, 17 ;send 18 bits including start and end bitloop_bit2: out pins, 1 [5] ;send 1 bit set x, 31 [30]loop_inner2: nop [31] jmp x--loop_inner2 jmp y--loop_bit2 set pindirs, 0 ;set pin input wait 1 gpio SC_PIN ;wait end transmission .wrapStatistics: Posted by Jerahya — Thu Nov 07, 2024 6:21 pm — Replies 2 — Views 65