diff options
| author | Daniel Friesel <derf@finalrewind.org> | 2018-08-07 10:18:25 +0200 |
|---|---|---|
| committer | Daniel Friesel <derf@finalrewind.org> | 2018-08-07 10:18:25 +0200 |
| commit | f6a842b1b064c83d42dfd626e888f79e4c1633e8 (patch) | |
| tree | 5fb6088e10bd7fec2855a4c2a4914812e33a1be3 /src/driver | |
| parent | 353aa77910b3a9eeb8282539b17c76c7c7ec0dc7 (diff) | |
Support optional SoftI2C pullups on MSP430
Diffstat (limited to 'src/driver')
| -rw-r--r-- | src/driver/soft_i2c.cc | 51 |
1 files changed, 32 insertions, 19 deletions
diff --git a/src/driver/soft_i2c.cc b/src/driver/soft_i2c.cc index 94ab261..e7b8548 100644 --- a/src/driver/soft_i2c.cc +++ b/src/driver/soft_i2c.cc @@ -1,32 +1,45 @@ #include "driver/soft_i2c.h" #include "driver/gpio.h" +#include "arch.h" + +#ifdef SOFTI2C_PULLUP +#define SDA_HIGH gpio.input(sda, 1) +#define SDA_LOW gpio.output(sda, 0) +#define SCL_HIGH gpio.input(scl, 1) +#define SCL_LOW gpio.output(scl, 0) +#else +#define SDA_HIGH gpio.input(sda) +#define SDA_LOW gpio.output(sda) +#define SCL_HIGH gpio.input(scl) +#define SCL_LOW gpio.output(scl) +#endif signed char SoftI2C::setup() { - gpio.write(sda, 0); - gpio.write(scl, 0); + SDA_HIGH; + SCL_HIGH; return 0; } void SoftI2C::start() { - gpio.input(sda); - gpio.input(scl); + SDA_HIGH; + SCL_HIGH; // - gpio.output(sda); + SDA_LOW; // - gpio.output(scl); + SCL_LOW; } void SoftI2C::stop() { - gpio.output(scl); + SCL_LOW; // - gpio.output(sda); + SDA_LOW; // - gpio.input(scl); + SCL_HIGH; // - gpio.input(sda); + SDA_HIGH; } bool SoftI2C::tx(unsigned char byte) @@ -34,20 +47,20 @@ bool SoftI2C::tx(unsigned char byte) unsigned char got_ack = 0; for (unsigned char i = 0; i <= 8; i++) { if ((byte & 0x80) || (i == 8)) { - gpio.input(sda); + SDA_HIGH; } else { - gpio.output(sda); + SDA_LOW; } byte <<= 1; // - gpio.input(scl); + SCL_HIGH; // if (i == 8) { if (!gpio.read(sda)) { got_ack = 1; } } - gpio.output(scl); + SCL_LOW; // } return got_ack; @@ -56,21 +69,21 @@ bool SoftI2C::tx(unsigned char byte) unsigned char SoftI2C::rx(bool send_ack) { unsigned char byte = 0; - gpio.input(sda); + SDA_HIGH; for (unsigned char i = 0; i <= 8; i++) { // - gpio.input(scl); + SCL_HIGH; // if ((i < 8) && gpio.read(sda)) { byte |= 1 << (7 - i); } // - gpio.output(scl); + SCL_LOW; // if ((i == 7) && send_ack) { - gpio.output(sda); + SDA_LOW; } else if ((i == 8) && send_ack) { - gpio.input(sda); + SDA_HIGH; } } return byte; |