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-rw-r--r--Makefile5
-rw-r--r--include/driver/soft_i2c.h26
-rw-r--r--src/driver/soft_i2c.cc121
3 files changed, 152 insertions, 0 deletions
diff --git a/Makefile b/Makefile
index a6f03c9..b7089b4 100644
--- a/Makefile
+++ b/Makefile
@@ -27,6 +27,11 @@ ifneq ($(findstring sharp96,${drivers}), )
COMMON_FLAGS += -DSHARP96_CS_PIN=GPIO::${sharp96_cs_pin}
endif
+ifneq ($(findstring softi2c,${drivers}), )
+ TARGETS += src/driver/soft_i2c.cc
+ COMMON_FLAGS += -DDRIVER_SOFTI2C
+endif
+
ifeq (${timer_cycles}, 1)
COMMON_FLAGS += -DTIMER_CYCLES
endif
diff --git a/include/driver/soft_i2c.h b/include/driver/soft_i2c.h
new file mode 100644
index 0000000..aff63e3
--- /dev/null
+++ b/include/driver/soft_i2c.h
@@ -0,0 +1,26 @@
+#ifndef SOFTI2C_H
+#define SOFTI2C_H
+
+class SoftI2C {
+ private:
+ SoftI2C(const SoftI2C &copy);
+
+ unsigned char sda, scl;
+
+ void start();
+ void stop();
+ bool tx(unsigned char byte);
+ unsigned char rx(bool send_ack);
+
+ public:
+ SoftI2C(unsigned char sda, unsigned char scl) : sda(sda), scl(scl) {}
+ signed char setup();
+ void scan(unsigned int *results);
+ signed char xmit(unsigned char address,
+ unsigned char tx_len, unsigned char *tx_buf,
+ unsigned char rx_len, unsigned char *rx_buf);
+};
+
+extern SoftI2C i2c;
+
+#endif
diff --git a/src/driver/soft_i2c.cc b/src/driver/soft_i2c.cc
new file mode 100644
index 0000000..f8ee052
--- /dev/null
+++ b/src/driver/soft_i2c.cc
@@ -0,0 +1,121 @@
+#include "driver/soft_i2c.h"
+#include "driver/gpio.h"
+
+signed char SoftI2C::setup()
+{
+ gpio.write(sda, 0);
+ gpio.write(scl, 0);
+ return 0;
+}
+
+void SoftI2C::start()
+{
+ gpio.input(sda);
+ gpio.input(scl);
+ //
+ gpio.output(sda);
+ //
+ gpio.output(scl);
+}
+
+void SoftI2C::stop()
+{
+ gpio.output(sda);
+ //
+ gpio.input(scl);
+ //
+ gpio.input(sda);
+}
+
+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);
+ } else {
+ gpio.output(sda);
+ }
+ byte <<= 1;
+ //
+ gpio.input(scl);
+ //
+ if (i == 8) {
+ if (!gpio.read(sda)) {
+ got_ack = 1;
+ }
+ }
+ gpio.output(scl);
+ //
+ }
+ return got_ack;
+}
+
+unsigned char SoftI2C::rx(bool send_ack)
+{
+ unsigned char byte = 0;
+ gpio.input(sda);
+ for (unsigned char i = 0; i <= 8; i++) {
+ //
+ gpio.input(scl);
+ //
+ if ((i < 8) && gpio.read(sda)) {
+ byte |= 1 << (7 - i);
+ }
+ //
+ gpio.output(scl);
+ //
+ if ((i == 7) && send_ack) {
+ gpio.output(sda);
+ } else if ((i == 8) && send_ack) {
+ gpio.input(sda);
+ }
+ }
+ return byte;
+}
+
+void SoftI2C::scan(unsigned int *results)
+{
+ unsigned char i2caddr;
+ for (unsigned char address = 0; address < 128; address++) {
+
+ i2caddr = (address << 1) | 1;
+
+ start();
+
+ if (tx(i2caddr)) {
+ results[address / (8 * sizeof(unsigned int))] |= 1 << (address % (8 * sizeof(unsigned int)));
+ }
+ }
+ stop();
+}
+
+signed char SoftI2C::xmit(unsigned char address,
+ unsigned char tx_len, unsigned char *tx_buf,
+ unsigned char rx_len, unsigned char *rx_buf)
+{
+ 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] = rx((i < rx_len) * 1);
+ }
+ }
+
+ stop();
+
+ return 0;
+}
+
+SoftI2C i2c(GPIO::p1_6, GPIO::p1_7);