Revision 0:b8fa872b60e6, committed 2016-06-10

Comitter:

jk1lot

Date:

Fri Jun 10 14:27:27 2016 +0000

Commit message:

first published version

Changed in this revision

diff -r 000000000000 -r b8fa872b60e6 TC77.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/TC77.cpp	Fri Jun 10 14:27:27 2016 +0000
@@ -0,0 +1,55 @@
+#include "TC77.h"
+
+TC77::TC77(SPI *s, PinName pin):spi(s),cs(pin)
+{
+    cs=1;
+    spi->format(16);
+    spi->frequency(100*1000);
+    start();
+}
+
+void TC77::start(void)
+{
+    write(0x0000);
+    //shutdownモードからの復帰には最大400ms掛かる（データシートより）
+    wait_ms(400);
+}
+
+uint16_t TC77::id(void)
+{
+    shutdown();
+    int16_t v=write(0x0000);
+    wait_ms(400);
+    return v;
+}
+
+float TC77::temperature(void)
+{
+    int16_t t0=read();
+    //bit2が0のときは測定が終わっていないので値は不正
+    while((t0&0x0004)==0) {
+        wait_ms(400);
+        t0=read();
+    }
+    return ((signed int)t0>>3)*0.0625f;
+}
+
+//TC77は読み取りと書込みが同時には出来ない
+//16bit読み込むと次の16bitが書込みになる
+int16_t TC77::write(int16_t command)
+{
+    cs=0;
+    int16_t v=spi->write(0x0000);
+    spi->write(command);
+    cs=1;
+    return v;
+}
+
+//読むだけならば16bitのやり取りで良い
+int16_t TC77::read(void)
+{
+    cs=0;
+    int16_t v=spi->write(0x0000);
+    cs=1;
+    return v;
+}

diff -r 000000000000 -r b8fa872b60e6 TC77.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/TC77.h	Fri Jun 10 14:27:27 2016 +0000
@@ -0,0 +1,73 @@
+/*
+ * TC77 SPI Thermal Sensor
+ *
+ *  mbed                 TC77
+ *  MOSI ---R 10K---+
+ *                  |
+ *  MISO -----------+--- pin1 SI/O.
+ *  SCK  --------------- pin2 SCK.
+ *  CS   --------------- pin7 CS(active low).
+ *
+ */
+
+#ifndef TC77_H
+#define TC77_H
+
+#include "mbed.h"
+
+/** TC77 SPI Thermal Sensor chip
+ *
+ * @note pin connection
+ * @code
+ * mbed                 TC77device
+ * MOSI ---R 10K---+
+ *                 |
+ * MISO -----------+--- pin1 SI/O
+ * SCK  --------------- pin2 SCK
+ * CS   --------------- pin7 CS(active low)
+ * @endcode
+ *
+@note sample program
+@code
+#include "mbed.h"
+#include "TC77.h"
+
+SPI spi1(p5,p6,p7);
+TC77 tc77(&spi1, p8);
+
+int main() {
+    while(true) {
+        printf("%.1f \r\n",tc77.temperature());
+        wait(1.0);
+    }
+}
+@endcode
+*/
+class TC77
+{
+    SPI *spi;
+    DigitalOut cs;
+public:
+    //! @param s pointer to SPI object
+    //! @param pin PinName of CS
+    TC77(SPI *s, PinName pin);
+
+    //! go to shutdown mode(power save)
+    inline void shutdown(void) {write(0xffff);}
+    //! start from shutdown mode
+    void start(void);
+    //! get device ID
+    uint16_t id(void);
+    //! get temperature @return Temperature value, expressed in degrees Celsius
+    float temperature(void);
+protected:
+    //! read data and send command.
+    //! It is impossible in the TC77 to perform the writing and reading at the same time.
+    //! After reading 16bit, TC77 is ready to write. So total transferred bit is 32. 
+    int16_t write(int16_t command);
+    //! read data.
+    //! transferred 16bit only
+    int16_t read(void);
+};
+
+#endif
\ No newline at end of file