Skip to content

new CAN API demo #5211

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Draft
soypat wants to merge 5 commits into
base: dev
Choose a base branch
from
+340 −420
Draft

new CAN API demo #5211

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
5 commits
Select commit Hold shift + click to select a range
ab087d6
new CAN API demo
soypat Feb 20, 2026
a5292ec
full CAN API refactor
soypat Feb 20, 2026
25f5f76
add interrupts
soypat Feb 21, 2026
ef05ba2
delete old can
soypat Feb 21, 2026
c5cb58c
take @knieriem suggestions and apply them to can.go
soypat Mar 1, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
2 changes: 1 addition & 1 deletion src/machine/board_amken_trio.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -135,7 +135,7 @@ var (

// FDCAN1 on PD0 (RX) / PD1 (TX) with onboard transceiver
CAN1 = &_CAN1
_CAN1 = FDCAN{
_CAN1 = CAN{
Bus: stm32.FDCAN1,
TxAltFuncSelect: AF3_FDCAN1_FDCAN2,
RxAltFuncSelect: AF3_FDCAN1_FDCAN2,
Expand Down
4 changes: 2 additions & 2 deletions src/machine/board_nucleog0b1re.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -107,7 +107,7 @@ var (

// FDCAN1 on PA11 (TX) / PA12 (RX)
CAN1 = &_CAN1
_CAN1 = FDCAN{
_CAN1 = CAN{
Bus: stm32.FDCAN1,
TxAltFuncSelect: AF9_FDCAN1_FDCAN2,
RxAltFuncSelect: AF9_FDCAN1_FDCAN2,
Expand All @@ -116,7 +116,7 @@ var (

// FDCAN2 on PD12 (TX) / PD13 (RX)
CAN2 = &_CAN2
_CAN2 = FDCAN{
_CAN2 = CAN{
Bus: stm32.FDCAN2,
TxAltFuncSelect: AF3_FDCAN1_FDCAN2,
RxAltFuncSelect: AF3_FDCAN1_FDCAN2,
Expand Down
100 changes: 100 additions & 0 deletions src/machine/can.go
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,100 @@
//go:build stm32g0

package machine

// unexported functions here are implemented in the device file
// and added to the build tags of this file.

// These types are an alias for documentation purposes exclusively. We wish
// the interface to be used by other ecosystems besides TinyGo which is why
// we need these types to be a primitive types at the interface level.
// If these types are defined at machine or machine/can level they are not
// usable by non-TinyGo projects. This is not good news for fostering wider adoption
// of our API in "big-Go" embedded system projects like TamaGo and periph.io
type (
// CAN IDs in tinygo are represented as 30 bit integers where
// bits 1..29 store the actual ID and the 30th bit stores the IDE bit (if extended ID).
// We include the extended ID bit in the ID itself to make comparison of IDs easier for users
// since two identical IDs where one is extended and one is not are NOT equivalent IDs.
canID = uint32
// CAN flags bitmask are defined below.
canFlags = uint32
)

// CAN ID definitions.
const (
canIDStdMask canID = (1 << 11) - 1
canIDExtendedMask canID = (1 << 29) - 1
canIDExtendedBit canID = 1 << 30
)

// CAN Flag bit definitions.
const (
canFlagBRS canFlags = 1 << 0 // Bit Rate Switch active on tx/rx of frame.
canFlagFDF canFlags = 1 << 1 // Is a FD Frame.
canFlagRTR canFlags = 1 << 2 // is a retransmission request frame.
canFlagESI canFlags = 1 << 3 // Error status indicator active on tx/rx of frame.
canFlagIDE canFlags = 1 << 4 // Extended ID.
)

// TxFIFOLevel returns amount of CAN frames stored for transmission and total Tx fifo length.
func (can *CAN) TxFIFOLevel() (level int, maxlevel int) {
return can.txFIFOLevel()
}

// Tx puts a CAN frame in TxFIFO for transmission. Returns error if TxFIFO is full.
func (can *CAN) Tx(id canID, flags canFlags, data []byte) error {
return can.tx(id, extendedID, data)
}

// RxFIFOLevel returns amount of CAN frames received and stored and total Rx fifo length.
// If the hardware is interrupt driven RxFIFOLevel should return 0,0.
func (can *CAN) RxFIFOLevel() (level int, maxlevel int) {
return can.rxFIFOLevel()
}

// SetRxCallback sets the receive callback. See [canFlags] for information on how bits are layed out.
func (can *CAN) SetRxCallback(cb func(data []byte, id canID, timestamp uint32, flags canFlags)) {
can.setRxCallback(cb)
}

// RxPoll is called periodically for poll driven drivers. If the driver is interrupt driven
// then RxPoll is a no-op and may return nil. Users may determine if a CAN is interrupt driven by
// checking if RxFIFOLevel returns 0,0.
func (can *CAN) RxPoll() error {
return can.rxPoll()
}

// DLC to bytes lookup table
var dlcToBytes = [16]byte{0, 1, 2, 3, 4, 5, 6, 7, 8, 12, 16, 20, 24, 32, 48, 64}

// dlcToLength converts a DLC value to actual byte length
func dlcToLength(dlc byte) uint8 {
if dlc > 15 {
dlc = 15
}
return dlcToBytes[dlc]
}

// lengthToDLC converts a byte length to DLC value
func lengthToDLC(length uint8) (dlc byte) {
switch {
case length <= 8:
dlc = length
case length <= 12:
dlc = 9
case length <= 16:
dlc = 10
case length <= 20:
dlc = 11
case length <= 24:
dlc = 12
case length <= 32:
dlc = 13
case length <= 48:
dlc = 14
default:
dlc = 15
}
return dlc
}
Loading
Loading