From 63cbb8facd9d9dc016f902bb312283f0b5f8d055 Mon Sep 17 00:00:00 2001 From: Daniel Friesel Date: Fri, 26 Oct 2018 08:58:18 +0200 Subject: Merge SoftI2C timer={0,1} code paths, adjust timing according to I2C spec It's occasionally slower than specified, but should never be too fast --- src/arch/msp430fr5969lp/arch.cc | 10 ++- src/driver/soft_i2c.cc | 184 ++++++---------------------------------- 2 files changed, 33 insertions(+), 161 deletions(-) (limited to 'src') diff --git a/src/arch/msp430fr5969lp/arch.cc b/src/arch/msp430fr5969lp/arch.cc index cde0503..1eb34b5 100644 --- a/src/arch/msp430fr5969lp/arch.cc +++ b/src/arch/msp430fr5969lp/arch.cc @@ -104,8 +104,14 @@ volatile char run_loop = 0; void Arch::delay_us(unsigned int const us) { - for (unsigned int i = 0; i < us/10; i++) { - __delay_cycles(F_CPU / 100000UL); + if (us < 10) { + for (unsigned int i = 0; i < us; i++) { + __delay_cycles(F_CPU / 1000000UL); + } + } else { + for (unsigned int i = 0; i < us/10; i++) { + __delay_cycles(F_CPU / 100000UL); + } } } void Arch::delay_ms(unsigned int const ms) diff --git a/src/driver/soft_i2c.cc b/src/driver/soft_i2c.cc index 3679514..6c36b6f 100644 --- a/src/driver/soft_i2c.cc +++ b/src/driver/soft_i2c.cc @@ -11,6 +11,7 @@ #error "SOFTI2C_TIMER and TIMER_CYCLES are mutually exclusive" #endif #include "driver/timer.h" +volatile unsigned char timer_done = 0; #endif #ifdef SOFTI2C_PULLUP_INTERNAL @@ -30,171 +31,33 @@ #define SCL_LOW gpio.output(scl) #endif /* SOFTI2C_PULLUP */ -#ifndef SOFTI2C_TIMER - -#if F_I2C < 50000 -#define I2C_WAIT arch.delay_us((500000UL / F_I2C) - 10) -#else -#define I2C_WAIT -#endif /* !SOFTI2C_TIMER */ - -signed char SoftI2C::setup() -{ -#ifdef SOFTI2C_PULLUP_EXTERNAL - gpio.output(sda_pull); - gpio.output(scl_pull); -#endif -#ifdef SOFTI2C_PULLUP_FIXED_GPIO -#if MULTIPASS_ARCH_msp430fr5969lp - gpio.output(GPIO::p1_4, 1); - gpio.output(GPIO::p1_5, 1); -#else -#error "softi2c_pullup=gpio not supported on this architecture" -#endif /* MULTIPASS_ARCH_* */ -#endif /* SOFTI2C_PULLUP_FIXED_GPIO */ - SDA_HIGH; - SCL_HIGH; - return 0; -} - -void SoftI2C::start() -{ - SDA_HIGH; - SCL_HIGH; - I2C_WAIT; - SDA_LOW; - I2C_WAIT; - SCL_LOW; -} - -void SoftI2C::stop() -{ - SCL_LOW; - I2C_WAIT; - SDA_LOW; - I2C_WAIT; - SCL_HIGH; - I2C_WAIT; - SDA_HIGH; -} - -bool SoftI2C::tx(unsigned char byte) -{ - unsigned char got_ack = 0; - for (unsigned char i = 0; i <= 8; i++) { - if ((byte & 0x80) || (i == 8)) { - SDA_HIGH; - } else { - SDA_LOW; - } - byte <<= 1; - I2C_WAIT; - SCL_HIGH; - while (!gpio.read(scl)) ; - I2C_WAIT; - if (i == 8) { - if (!gpio.read(sda)) { - got_ack = 1; - } - } - SCL_LOW; - I2C_WAIT; - } - return got_ack; -} - -unsigned char SoftI2C::rx(bool send_ack) -{ - unsigned char byte = 0; - SDA_HIGH; - for (unsigned char i = 0; i <= 8; i++) { - I2C_WAIT; - SCL_HIGH; - while (!gpio.read(scl)) ; - I2C_WAIT; - if ((i < 8) && gpio.read(sda)) { - byte |= 1 << (7 - i); - } - I2C_WAIT; - SCL_LOW; - I2C_WAIT; - if ((i == 7) && send_ack) { - SDA_LOW; - } else if ((i == 8) && send_ack) { - SDA_HIGH; - } - } - return byte; -} - -void SoftI2C::scan(unsigned int *results) -{ - unsigned char i2caddr; - for (unsigned char address = 0; address < 128; address++) { - - i2caddr = (address << 1) | 0; - start(); - - if (tx(i2caddr)) { - results[address / (8 * sizeof(unsigned int))] |= 1 << (address % (8 * sizeof(unsigned int))); - stop(); - } - } - stop(); -} - -signed char SoftI2C::xmit(unsigned char address, - unsigned char tx_len, unsigned char *tx_buf, - unsigned char rx_len, unsigned char *rx_buf) +inline void i2c_wait() { - unsigned char i; - - if (tx_len) { - start(); - tx((address << 1) | 0); - - for (i = 0; i < tx_len; i++) { - tx(tx_buf[i]); - } - } - if (rx_len) { - start(); - tx((address << 1) | 1); - - for (i = 1; i <= rx_len; i++) { - rx_buf[i-1] = rx((i < rx_len) * 1); - } - } - - stop(); - - return 0; -} - -#else - -volatile unsigned char timer_done = 0; - +#ifdef SOFTI2C_TIMER /* - * Note: On MSP430, if F_CPU / F_I2C < 60 (approx.), await_timer() does not + * Note: On MSP430, if F_CPU / F_I2C < 60 (approx.), i2c_wait() does not * work. Probably related to missed interrupts / not enough cycles between * start and idle? We work around this for now by simulating an immediate * return in these cases. */ #if MULTIPASS_ARCH_msp430fr5969lp && ((F_CPU / F_I2C) < 60) -inline void await_timer() {} #else -inline void await_timer() -{ timer_done = 0; timer.start(1); while (!timer_done) { arch.idle(); } timer.stop(); -} #endif +#else /* !SOFTI2C_TIMER */ +#if (500000UL / F_I2C) > 11 + arch.delay_us((500000UL / F_I2C) - 10); +#else + arch.delay_us(500000UL / F_I2C); +#endif +#endif /* SOFTI2C_TIMER */ +} signed char SoftI2C::setup() { @@ -212,6 +75,7 @@ signed char SoftI2C::setup() #endif /* SOFTI2C_PULLUP_FIXED_GPIO */ SDA_HIGH; SCL_HIGH; +#ifdef SOFTI2C_TIMER /* * I2C frequency is the time between two SCL low->high transitions * (or high->low, whatever you prefer). For the timer, we need to set the @@ -221,6 +85,7 @@ signed char SoftI2C::setup() * Timer Freq [kHz] = I2C Freq [Hz] * 2 / 1000 */ timer.setup_khz(F_I2C / 500); +#endif return 0; } @@ -228,21 +93,22 @@ void SoftI2C::start() { SDA_HIGH; SCL_HIGH; - await_timer(); + i2c_wait(); // t_{SU,STA} >= 4.7 µs (für Sr) SDA_LOW; - await_timer(); + i2c_wait(); // t_{HD,STA} >= 4 µs SCL_LOW; - await_timer(); + i2c_wait(); } void SoftI2C::stop() { SCL_LOW; SDA_LOW; - await_timer(); + i2c_wait(); SCL_HIGH; - await_timer(); + i2c_wait(); // t_{SU,STO} >= 4 µs SDA_HIGH; + i2c_wait(); // t_{BUF} >= 4.7 µs } bool SoftI2C::tx(unsigned char byte) @@ -255,8 +121,9 @@ bool SoftI2C::tx(unsigned char byte) SDA_LOW; } byte <<= 1; + i2c_wait(); SCL_HIGH; - await_timer(); + i2c_wait(); while (!gpio.read(scl)) ; if (i == 8) { if (!gpio.read(sda)) { @@ -264,7 +131,6 @@ bool SoftI2C::tx(unsigned char byte) } } SCL_LOW; - await_timer(); } return got_ack; } @@ -274,14 +140,14 @@ unsigned char SoftI2C::rx(bool send_ack) unsigned char byte = 0; SDA_HIGH; for (unsigned char i = 0; i <= 8; i++) { + i2c_wait(); SCL_HIGH; - await_timer(); + i2c_wait(); while (!gpio.read(scl)) ; if ((i < 8) && gpio.read(sda)) { byte |= 1 << (7 - i); } SCL_LOW; - await_timer(); if ((i == 7) && send_ack) { SDA_LOW; } else if ((i == 8) && send_ack) { @@ -336,10 +202,10 @@ signed char SoftI2C::xmit(unsigned char address, return 0; } +#ifdef SOFTI2C_TIMER ON_TIMER_INTERRUPT_head timer_done = 1; ON_TIMER_INTERRUPT_tail - #endif #if SOFTI2C_PULLUP_EXTERNAL -- cgit v1.2.3