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Add MCP2515::setClkOut() to allow use of the CLKOUT prescaler #19

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Merged
merged 2 commits into from
Jul 15, 2019
Merged

Add MCP2515::setClkOut() to allow use of the CLKOUT prescaler #19

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fb38040
add MCP2515::setClkOut() to allow use of the CLKOUT prescaler
leres Jul 14, 2019
e19547d
Add 33.333kbps and 83.333kbps support for 20 MHz using values
leres Jul 15, 2019
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44 changes: 40 additions & 4 deletions mcp2515.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -226,7 +226,7 @@ MCP2515::ERROR MCP2515::setBitrate(const CAN_SPEED canSpeed, CAN_CLOCK canClock)
cfg3 = MCP_8MHz_31k25BPS_CFG3;
break;

case (CAN_33KBPS): // 33.33KBPS
case (CAN_33KBPS): // 33.333KBPS
cfg1 = MCP_8MHz_33k3BPS_CFG1;
cfg2 = MCP_8MHz_33k3BPS_CFG2;
cfg3 = MCP_8MHz_33k3BPS_CFG3;
Expand Down Expand Up @@ -313,7 +313,7 @@ MCP2515::ERROR MCP2515::setBitrate(const CAN_SPEED canSpeed, CAN_CLOCK canClock)
cfg3 = MCP_16MHz_20kBPS_CFG3;
break;

case (CAN_33KBPS): // 20Kbps
case (CAN_33KBPS): // 33.333Kbps
cfg1 = MCP_16MHz_33k3BPS_CFG1;
cfg2 = MCP_16MHz_33k3BPS_CFG2;
cfg3 = MCP_16MHz_33k3BPS_CFG3;
Expand All @@ -336,7 +336,7 @@ MCP2515::ERROR MCP2515::setBitrate(const CAN_SPEED canSpeed, CAN_CLOCK canClock)
cfg3 = MCP_16MHz_80kBPS_CFG3;
break;

case (CAN_83K3BPS): // 83.3333Kbps
case (CAN_83K3BPS): // 83.333Kbps
cfg1 = MCP_16MHz_83k3BPS_CFG1;
cfg2 = MCP_16MHz_83k3BPS_CFG2;
cfg3 = MCP_16MHz_83k3BPS_CFG3;
Expand Down Expand Up @@ -387,6 +387,12 @@ MCP2515::ERROR MCP2515::setBitrate(const CAN_SPEED canSpeed, CAN_CLOCK canClock)
case (MCP_20MHZ):
switch (canSpeed)
{
case (CAN_33KBPS): // 33.333Kbps
cfg1 = MCP_20MHz_33k3BPS_CFG1;
cfg2 = MCP_20MHz_33k3BPS_CFG2;
cfg3 = MCP_20MHz_33k3BPS_CFG3;
break;

case (CAN_40KBPS): // 40Kbps
cfg1 = MCP_20MHz_40kBPS_CFG1;
cfg2 = MCP_20MHz_40kBPS_CFG2;
Expand All @@ -405,6 +411,12 @@ MCP2515::ERROR MCP2515::setBitrate(const CAN_SPEED canSpeed, CAN_CLOCK canClock)
cfg3 = MCP_20MHz_80kBPS_CFG3;
break;

case (CAN_83K3BPS): // 83.333Kbps
cfg1 = MCP_20MHz_83k3BPS_CFG1;
cfg2 = MCP_20MHz_83k3BPS_CFG2;
cfg3 = MCP_20MHz_83k3BPS_CFG3;
break;

case (CAN_100KBPS): // 100Kbps
cfg1 = MCP_20MHz_100kBPS_CFG1;
cfg2 = MCP_20MHz_100kBPS_CFG2;
Expand Down Expand Up @@ -452,7 +464,6 @@ MCP2515::ERROR MCP2515::setBitrate(const CAN_SPEED canSpeed, CAN_CLOCK canClock)
break;
}


if (set) {
setRegister(MCP_CNF1, cfg1);
setRegister(MCP_CNF2, cfg2);
Expand All @@ -464,6 +475,31 @@ MCP2515::ERROR MCP2515::setBitrate(const CAN_SPEED canSpeed, CAN_CLOCK canClock)
}
}

MCP2515::ERROR MCP2515::setClkOut(const CAN_CLKOUT divisor)
{
ERROR res;
uint8_t cfg3;

if (divisor == CLKOUT_DISABLE) {
/* Turn off CLKEN */
modifyRegister(MCP_CANCTRL, CANCTRL_CLKEN, 0x00);

/* Turn on CLKOUT for SOF */
modifyRegister(MCP_CNF3, CNF3_SOF, CNF3_SOF);
return ERROR_OK;
}

/* Set the prescaler (CLKPRE) */
modifyRegister(MCP_CANCTRL, CANCTRL_CLKPRE, divisor);

/* Turn on CLKEN */
modifyRegister(MCP_CANCTRL, CANCTRL_CLKEN, CANCTRL_CLKEN);

/* Turn off CLKOUT for SOF */
modifyRegister(MCP_CNF3, CNF3_SOF, 0x00);
return ERROR_OK;
}

void MCP2515::prepareId(uint8_t *buffer, const bool ext, const uint32_t id)
{
uint16_t canid = (uint16_t)(id & 0x0FFFF);
Expand Down
20 changes: 19 additions & 1 deletion mcp2515.h
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Original file line number Diff line number Diff line change
Expand Up @@ -149,6 +149,10 @@
#define MCP_20MHz_100kBPS_CFG2 (0xFA)
#define MCP_20MHz_100kBPS_CFG3 (0x87)

#define MCP_20MHz_83k3BPS_CFG1 (0x04)
#define MCP_20MHz_83k3BPS_CFG2 (0xFE)
#define MCP_20MHz_83k3BPS_CFG3 (0x87)

#define MCP_20MHz_80kBPS_CFG1 (0x04)
#define MCP_20MHz_80kBPS_CFG2 (0xFF)
#define MCP_20MHz_80kBPS_CFG3 (0x87)
Expand All @@ -161,6 +165,10 @@
#define MCP_20MHz_40kBPS_CFG2 (0xFF)
#define MCP_20MHz_40kBPS_CFG3 (0x87)

#define MCP_20MHz_33k3BPS_CFG1 (0x0B)
#define MCP_20MHz_33k3BPS_CFG2 (0xFF)
#define MCP_20MHz_33k3BPS_CFG3 (0x87)

enum CAN_CLOCK {
MCP_20MHZ,
MCP_16MHZ,
Expand All @@ -186,6 +194,14 @@ enum CAN_SPEED {
CAN_1000KBPS
};

enum CAN_CLKOUT {
CLKOUT_DISABLE = -1,
CLKOUT_DIV1 = 0x0,
CLKOUT_DIV2 = 0x1,
CLKOUT_DIV4 = 0x2,
CLKOUT_DIV8 = 0x3,
};

class MCP2515
{
public:
Expand Down Expand Up @@ -264,6 +280,8 @@ class MCP2515
static const uint8_t CANSTAT_OPMOD = 0xE0;
static const uint8_t CANSTAT_ICOD = 0x0E;

static const uint8_t CNF3_SOF = 0x80;

static const uint8_t TXB_EXIDE_MASK = 0x08;
static const uint8_t DLC_MASK = 0x0F;
static const uint8_t RTR_MASK = 0x40;
Expand Down Expand Up @@ -298,7 +316,6 @@ class MCP2515
TXB_TXP = 0x03
};


static const uint8_t EFLG_ERRORMASK = EFLG_RX1OVR
| EFLG_RX0OVR
| EFLG_TXBO
Expand Down Expand Up @@ -446,6 +463,7 @@ class MCP2515
ERROR setSleepMode();
ERROR setLoopbackMode();
ERROR setNormalMode();
ERROR setClkOut(const CAN_CLKOUT divisor);
ERROR setBitrate(const CAN_SPEED canSpeed);
ERROR setBitrate(const CAN_SPEED canSpeed, const CAN_CLOCK canClock);
ERROR setFilterMask(const MASK num, const bool ext, const uint32_t ulData);
Expand Down