Skip to content
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

Issue2524 allow clocks below 100KHz #6934

Merged
merged 11 commits into from
Dec 28, 2019
Merged

Issue2524 allow clocks below 100KHz #6934

Changes from all commits
Commits
Show all changes
11 commits
Select commit Hold shift + click to select a range
1f782bd
change bus clock (busywait) to be programmable [issue 2524], remove u…
Tech-TX Dec 21, 2019
a931e1d
change bus clock (busywait) to be programmable [issue 2524], remove u…
Tech-TX Dec 21, 2019
0d2b130
change bus clock (busywait) to be programmable [issue 2524], remove u…
Tech-TX Dec 22, 2019
3923b10
Merge branch 'master' into issue2524
Tech-TX Dec 22, 2019
387ca51
correct for underflow < 233Hz
Tech-TX Dec 22, 2019
b22de4d
change bus clock (busywait) to be programmable [issue 2524], convert …
Tech-TX Dec 23, 2019
14aed48
Merge branch 'master' into issue2524
Tech-TX Dec 24, 2019
9cf1095
updated minimum I2C speed for calculated bus clock
Tech-TX Dec 28, 2019
505b813
Merge branch 'issue2524' of https://github.com/Tech-TX/Arduino into i…
Tech-TX Dec 28, 2019
2d90dce
Merge branch 'master' into issue2524
Tech-TX Dec 28, 2019
2fa7998
Merge branch 'master' into issue2524
Tech-TX Dec 28, 2019
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
141 changes: 39 additions & 102 deletions cores/esp8266/core_esp8266_si2c.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -40,8 +40,8 @@ extern "C" {
{
GPEC = (1 << twi_sda);
}
static inline __attribute__((always_inline)) bool SDA_READ(const int twi_sda)
{
static inline __attribute__((always_inline)) bool SDA_READ(const int twi_sda)
{
return (GPI & (1 << twi_sda)) != 0;
}
static inline __attribute__((always_inline)) void SCL_LOW(const int twi_scl)
Expand All @@ -52,8 +52,8 @@ extern "C" {
{
GPEC = (1 << twi_scl);
}
static inline __attribute__((always_inline)) bool SCL_READ(const int twi_scl)
{
static inline __attribute__((always_inline)) bool SCL_READ(const int twi_scl)
{
return (GPI & (1 << twi_scl)) != 0;
}

Expand All @@ -63,7 +63,7 @@ class Twi
{
private:
unsigned int preferred_si2c_clock = 100000;
unsigned char twi_dcount = 18;
uint32_t twi_dcount = 18;
unsigned char twi_sda = 0;
unsigned char twi_scl = 0;
unsigned char twi_addr = 0;
Expand Down Expand Up @@ -112,7 +112,7 @@ class Twi
bool _slaveEnabled = false;

// Internal use functions
void ICACHE_RAM_ATTR busywait(unsigned char v);
void ICACHE_RAM_ATTR busywait(unsigned int v);
devyte marked this conversation as resolved.
Show resolved Hide resolved
bool write_start(void);
bool write_stop(void);
bool write_bit(bool bit);
Expand Down Expand Up @@ -148,7 +148,6 @@ class Twi
void attachSlaveRxEvent(void (*function)(uint8_t*, size_t));
void attachSlaveTxEvent(void (*function)(void));
void ICACHE_RAM_ATTR reply(uint8_t ack);
void ICACHE_RAM_ATTR stop(void);
void ICACHE_RAM_ATTR releaseBus(void);
void enableSlave();
};
Expand All @@ -161,65 +160,25 @@ static Twi twi;

void Twi::setClock(unsigned int freq)
{
if (freq < 1000) // minimum freq 1000Hz to minimize slave timeouts and WDT resets
freq = 1000;

preferred_si2c_clock = freq;

#if F_CPU == FCPU80
if (freq <= 50000)
{
twi_dcount = 38; //about 50KHz
}
else if (freq <= 100000)
{
twi_dcount = 19; //about 100KHz
}
else if (freq <= 200000)
{
twi_dcount = 8; //about 200KHz
}
else if (freq <= 300000)
{
twi_dcount = 3; //about 300KHz
}
else if (freq <= 400000)
{
twi_dcount = 1; //about 400KHz
}
else
{
twi_dcount = 1; //about 400KHz
}

if (freq > 400000)
freq = 400000;
twi_dcount = (500000000 / freq); // half-cycle period in ns
twi_dcount = (1000*(twi_dcount - 1120)) / 62500; // (half cycle - overhead) / busywait loop time

#else
if (freq <= 50000)
{
twi_dcount = 64; //about 50KHz
}
else if (freq <= 100000)
{
twi_dcount = 32; //about 100KHz
}
else if (freq <= 200000)
{
twi_dcount = 14; //about 200KHz
}
else if (freq <= 300000)
{
twi_dcount = 8; //about 300KHz
}
else if (freq <= 400000)
{
twi_dcount = 5; //about 400KHz
}
else if (freq <= 500000)
{
twi_dcount = 3; //about 500KHz
}
else if (freq <= 600000)
{
twi_dcount = 2; //about 600KHz
}
else
{
twi_dcount = 1; //about 700KHz
}

if (freq > 800000)
freq = 800000;
twi_dcount = (500000000 / freq); // half-cycle period in ns
twi_dcount = (1000*(twi_dcount - 560)) / 31250; // (half cycle - overhead) / busywait loop time

#endif
}

Expand Down Expand Up @@ -262,18 +221,13 @@ void Twi::enableSlave()
}
}

void ICACHE_RAM_ATTR Twi::busywait(unsigned char v)
void ICACHE_RAM_ATTR Twi::busywait(unsigned int v)
{
unsigned int i;
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wunused-but-set-variable"
unsigned int reg;
for (i = 0; i < v; i++)
for (i = 0; i < v; i++) // loop time is 5 machine cycles: 31.25ns @ 160MHz, 62.5ns @ 80MHz
{
reg = GPI;
asm("nop"); // minimum element to keep GCC from optimizing this function out.
}
(void)reg;
#pragma GCC diagnostic pop
}

bool Twi::write_start(void)
Expand Down Expand Up @@ -518,35 +472,24 @@ void ICACHE_RAM_ATTR Twi::reply(uint8_t ack)
if (ack)
{
//TWCR = _BV(TWEN) | _BV(TWIE) | _BV(TWINT) | _BV(TWEA);
SCL_HIGH(twi.twi_scl); // _BV(TWINT)
twi_ack = 1; // _BV(TWEA)
SCL_HIGH(twi.twi_scl); // _BV(TWINT)
twi_ack = 1; // _BV(TWEA)
}
else
{
//TWCR = _BV(TWEN) | _BV(TWIE) | _BV(TWINT);
SCL_HIGH(twi.twi_scl); // _BV(TWINT)
twi_ack = 0; // ~_BV(TWEA)
SCL_HIGH(twi.twi_scl); // _BV(TWINT)
twi_ack = 0; // ~_BV(TWEA)
}
}

void ICACHE_RAM_ATTR Twi::stop(void)
devyte marked this conversation as resolved.
Show resolved Hide resolved
{
// send stop condition
//TWCR = _BV(TWEN) | _BV(TWIE) | _BV(TWEA) | _BV(TWINT) | _BV(TWSTO);
SCL_HIGH(twi.twi_scl); // _BV(TWINT)
twi_ack = 1; // _BV(TWEA)
busywait(5); // Maybe this should be here
SDA_HIGH(twi.twi_sda); // _BV(TWSTO)
// update twi state
twi_state = TWI_READY;
}

void ICACHE_RAM_ATTR Twi::releaseBus(void)
{
// release bus
//TWCR = _BV(TWEN) | _BV(TWIE) | _BV(TWEA) | _BV(TWINT);
SCL_HIGH(twi.twi_scl); // _BV(TWINT)
twi_ack = 1; // _BV(TWEA)
SCL_HIGH(twi.twi_scl); // _BV(TWINT)
twi_ack = 1; // _BV(TWEA)
SDA_HIGH(twi.twi_sda);

// update twi state
Expand Down Expand Up @@ -657,7 +600,6 @@ void ICACHE_RAM_ATTR Twi::onTwipEvent(uint8_t status)
break;
case TW_BUS_ERROR: // bus error, illegal stop/start
twi_error = TW_BUS_ERROR;
stop();
break;
}
}
Expand Down Expand Up @@ -718,11 +660,11 @@ void ICACHE_RAM_ATTR Twi::onSclChange(void)
unsigned int scl;

// Store bool return in int to reduce final code size.
sda = SDA_READ(twi.twi_sda);
scl = SCL_READ(twi.twi_scl);

twi.twip_status = 0xF8; // reset TWI status
twi.twip_status = 0xF8; // reset TWI status

int twip_state_mask = S2M(twi.twip_state);
IFSTATE(S2M(TWIP_START) | S2M(TWIP_REP_START) | S2M(TWIP_SLA_W) | S2M(TWIP_READ))
Expand Down Expand Up @@ -797,7 +739,7 @@ void ICACHE_RAM_ATTR Twi::onSclChange(void)
}
else
{
SCL_LOW(twi.twi_scl); // clock stretching
SCL_LOW(twi.twi_scl); // clock stretching
SDA_HIGH(twi.twi_sda);
twi.twip_mode = TWIPM_ADDRESSED;
if (!(twi.twi_data & 0x01))
Expand All @@ -815,7 +757,7 @@ void ICACHE_RAM_ATTR Twi::onSclChange(void)
}
else
{
SCL_LOW(twi.twi_scl); // clock stretching
SCL_LOW(twi.twi_scl); // clock stretching
SDA_HIGH(twi.twi_sda);
if (!twi.twi_ack)
{
Expand Down Expand Up @@ -893,7 +835,7 @@ void ICACHE_RAM_ATTR Twi::onSclChange(void)
}
else
{
SCL_LOW(twi.twi_scl); // clock stretching
SCL_LOW(twi.twi_scl); // clock stretching
if (twi.twi_ack && twi.twi_ack_rec)
{
twi.onTwipEvent(TW_ST_DATA_ACK);
Expand Down Expand Up @@ -939,7 +881,7 @@ void ICACHE_RAM_ATTR Twi::onSdaChange(void)
else IFSTATE(S2M(TWIP_START) | S2M(TWIP_REP_START) | S2M(TWIP_SEND_ACK) | S2M(TWIP_WAIT_ACK) | S2M(TWIP_SLA_R) | S2M(TWIP_REC_ACK) | S2M(TWIP_READ_ACK) | S2M(TWIP_RWAIT_ACK) | S2M(TWIP_WRITE))
{
// START or STOP
SDA_HIGH(twi.twi_sda); // Should not be necessary
SDA_HIGH(twi.twi_sda); // Should not be necessary
twi.onTwipEvent(TW_BUS_ERROR);
twi.twip_mode = TWIPM_WAIT;
twi.twip_state = TWIP_BUS_ERR;
Expand All @@ -949,7 +891,7 @@ void ICACHE_RAM_ATTR Twi::onSdaChange(void)
if (sda)
{
// STOP
SCL_LOW(twi.twi_scl); // clock stretching
SCL_LOW(twi.twi_scl); // generates a low SCL pulse after STOP
ets_timer_disarm(&twi.timer);
twi.twip_state = TWIP_IDLE;
twi.twip_mode = TWIPM_IDLE;
Expand Down Expand Up @@ -983,7 +925,7 @@ void ICACHE_RAM_ATTR Twi::onSdaChange(void)
else
{
// during first bit in byte transfer - ok
SCL_LOW(twi.twi_scl); // clock stretching
SCL_LOW(twi.twi_scl); // clock stretching
twi.onTwipEvent(TW_SR_STOP);
if (sda)
{
Expand Down Expand Up @@ -1018,11 +960,6 @@ extern "C" {
return twi.setAddress(a);
}

void twi_stop(void)
{
twi.stop();
}

void twi_setClock(unsigned int freq)
{
twi.setClock(freq);
Expand Down