147 lines
3.9 KiB
Go
147 lines
3.9 KiB
Go
package xbee
|
|
|
|
import (
|
|
"bytes"
|
|
"encoding/binary"
|
|
"errors"
|
|
)
|
|
|
|
// This code is handled slightly differently. Rather than use structs to represent
|
|
// the frame data, we instead use an interface that represents an AT command, and
|
|
// standalone functions that convert the AT command to frame data.
|
|
// this way, we can add command support without needing to compose structs.
|
|
// The downside is that it's more difficult to deal with.
|
|
//
|
|
// AT command responses are handled with a struct to get the response status code.
|
|
|
|
// an ATCmd is anything that has a Payload function that returns the given payload
|
|
// pre-formatted to be send over the wire, and a Cmd command that returns the 2-character
|
|
// ATcommand itself. It must also have a parse response function that takes the response struct.
|
|
type ATCmd interface {
|
|
Payload() []byte // converts the AT command options to the binary argument format
|
|
Cmd() [2]rune // returns the AT command string.
|
|
Parse(*ATCmdResponse) error // takes a command response and parses the data into itself.
|
|
}
|
|
|
|
// The AT command, in its raw format. we don't handle parameters since it's dealt with by
|
|
// the interface.
|
|
type RawATCmd []byte
|
|
|
|
// implements frameable. this is kinda stupid but makes it more safe.
|
|
func (b RawATCmd) Bytes() []byte {
|
|
return b
|
|
}
|
|
|
|
// EncodeATCommand takes an AT command and encodes it in the payload format.
|
|
// it takes the frame index (which can be zero) as well as if it should be queued or
|
|
// not. It encodes the AT command to be framed and sent over the wire and returns the packet
|
|
func encodeATCommand(cmd [2]byte, p []byte, idx uint8, queued bool) RawATCmd {
|
|
// we encode a new byte slice that contains the cmd + payload concatenated correclty.
|
|
// this is then used to make the command frame, which contains ID/Type/Queued or not.
|
|
// the ATCmdFrame can be converted to bytes to be sent over the wire once framed.
|
|
|
|
buf := new(bytes.Buffer)
|
|
|
|
// we change the frame type based on if it's queued.
|
|
if queued {
|
|
buf.WriteByte(byte(ATCmdQueueType))
|
|
} else {
|
|
buf.WriteByte(byte(ATCmdType))
|
|
}
|
|
|
|
// next is the provided frame identifier, used for callbacks.
|
|
buf.WriteByte(idx)
|
|
|
|
buf.WriteByte(byte(cmd[0]))
|
|
buf.WriteByte(byte(cmd[1]))
|
|
// the payload can be empty. This would make it a query.
|
|
buf.Write(p)
|
|
|
|
return buf.Bytes()
|
|
}
|
|
|
|
type ATCmdResponse struct {
|
|
Cmd string
|
|
Status ATCmdStatus
|
|
Data []byte
|
|
}
|
|
|
|
func ParseATCmdResponse(p []byte) (*ATCmdResponse, error) {
|
|
|
|
if p[0] != 0x88 {
|
|
return nil, errors.New("not an AT command response")
|
|
}
|
|
if len(p) < 5 {
|
|
return nil, errors.New("received partial AT command response")
|
|
}
|
|
resp := &ATCmdResponse{
|
|
Cmd: string(p[2:4]),
|
|
Status: ATCmdStatus(p[4]),
|
|
Data: p[5:],
|
|
}
|
|
return resp, nil
|
|
}
|
|
|
|
//go:generate stringer -output=at_cmd_status.go -type ATCmdStatus
|
|
type ATCmdStatus uint8
|
|
|
|
const (
|
|
ATCmdStatusOK ATCmdStatus = 0
|
|
ATCmdStatusErr ATCmdStatus = 1
|
|
|
|
ATCmdStatusInvalidCmd ATCmdStatus = 2
|
|
ATCmdStatusInvalidParam ATCmdStatus = 3
|
|
)
|
|
|
|
type RemoteATCmdReq struct {
|
|
Destination uint64
|
|
Options uint8
|
|
}
|
|
|
|
func encodeRemoteATCommand(at ATCmd, idx uint8, queued bool, destination uint64) RawATCmd {
|
|
|
|
// sizing take from
|
|
buf := new(bytes.Buffer)
|
|
|
|
buf.WriteByte(byte(RemoteCmdReqType))
|
|
|
|
buf.WriteByte(idx)
|
|
|
|
binary.Write(buf, binary.BigEndian, destination)
|
|
|
|
binary.Write(buf, binary.BigEndian, uint16(0xFFFE))
|
|
|
|
// set remote command options. if idx = 0, we set bit zero (disable ack)
|
|
// if queued is true, we clear bit one (if false we set it)
|
|
|
|
var options uint8 = 0
|
|
if idx == 0 {
|
|
options = options | 0x1
|
|
}
|
|
if !queued {
|
|
options = options | 0x2
|
|
}
|
|
buf.WriteByte(options)
|
|
|
|
// write AT command
|
|
cmd := at.Cmd()
|
|
buf.WriteByte(byte(cmd[0]))
|
|
buf.WriteByte(byte(cmd[1]))
|
|
|
|
// write payload.
|
|
buf.Write(at.Payload())
|
|
|
|
return buf.Bytes()
|
|
}
|
|
|
|
// let's actually define some AT commands now.
|
|
|
|
type NetworkDevice struct {
|
|
Addr XBeeAddr
|
|
Identifier string
|
|
DeviceType byte
|
|
ProfileNum uint16
|
|
MfrId uint16
|
|
RSSI byte
|
|
}
|