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Update core_esp8266_si2c.c (#3389)

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With this patch the set up clock rate survives a re-init that is done by many libraries several times.

This makes e.g. an accelerated OLED display possible with the adafruit libraries
This commit is contained in:
Christoph Gommel 2018-03-24 21:23:25 +01:00 committed by Develo
parent 6464ae0c79
commit 2105b8b06f
1 changed files with 5 additions and 2 deletions
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7
cores/esp8266/core_esp8266_si2c.c
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@ -22,6 +22,7 @@
#include "pins_arduino.h" #include "pins_arduino.h"
#include "wiring_private.h" #include "wiring_private.h"
unsigned int preferred_si2c_clock = 100000;
unsigned char twi_dcount = 18; unsigned char twi_dcount = 18;
static unsigned char twi_sda, twi_scl; static unsigned char twi_sda, twi_scl;
static uint32_t twi_clockStretchLimit; static uint32_t twi_clockStretchLimit;
@ -44,6 +45,7 @@ static uint32_t twi_clockStretchLimit;
#endif #endif
void twi_setClock(unsigned int freq){ void twi_setClock(unsigned int freq){
preferred_si2c_clock = freq;
#if F_CPU == FCPU80 #if F_CPU == FCPU80
if(freq <= 50000) twi_dcount = 38;//about 50KHz if(freq <= 50000) twi_dcount = 38;//about 50KHz
else if(freq <= 100000) twi_dcount = 19;//about 100KHz else if(freq <= 100000) twi_dcount = 19;//about 100KHz
@ -72,7 +74,7 @@ void twi_init(unsigned char sda, unsigned char scl){
twi_scl = scl; twi_scl = scl;
pinMode(twi_sda, INPUT_PULLUP); pinMode(twi_sda, INPUT_PULLUP);
pinMode(twi_scl, INPUT_PULLUP); pinMode(twi_scl, INPUT_PULLUP);
twi_setClock(100000); twi_setClock(preferred_si2c_clock);
twi_setClockStretchLimit(230); // default value is 230 uS twi_setClockStretchLimit(230); // default value is 230 uS
} }
@ -231,5 +233,6 @@ uint8_t twi_status() {
if(!twi_write_start()) if(!twi_write_start())
return I2C_SDA_HELD_LOW_AFTER_INIT; //line busy. SDA again held low by another device. 2nd master? return I2C_SDA_HELD_LOW_AFTER_INIT; //line busy. SDA again held low by another device. 2nd master?
return I2C_OK; //all ok return I2C_OK; //all ok
} }