stmhal: Change SPI phase spec to 0,1 to match standard conventions.

Was 1 or 2, now 0 or 1 (respectively).  0 means sample MISO on first
edge, 1 means sample on second edge.

Addresses issue #936.

3 files changed, 11 insertions, 10 deletions

diff --git a/stmhal/spi.c b/stmhal/spi.c
index 22dc66419..2decc38f6 100644
--- a/stmhal/spi.c
+++ b/stmhal/spi.c
@@ -49,11 +49,12 @@
 /// parameters to init the SPI bus:
 ///
 ///     from pyb import SPI
-///     spi = SPI(1, SPI.MASTER, baudrate=600000, polarity=1, phase=1, crc=0x7)
+///     spi = SPI(1, SPI.MASTER, baudrate=600000, polarity=1, phase=0, crc=0x7)
 ///
 /// Only required parameter is mode, SPI.MASTER or SPI.SLAVE.  Polarity can be
-/// 0 or 1, and is the level the idle clock line sits at.  Phase can be 1 or 2
-/// for number of edges.  Crc can be None for no CRC, or a polynomial specifier.
+/// 0 or 1, and is the level the idle clock line sits at.  Phase can be 0 or 1
+/// to sample data on the first or second clock edge respectively.  Crc can be
+/// None for no CRC, or a polynomial specifier.
 ///
 /// Additional method for SPI:
 ///
@@ -223,7 +224,7 @@ STATIC void pyb_spi_print(void (*print)(void *env, const char *fmt, ...), void *
         } else {
             print(env, "SPI(%u, SPI.SLAVE", spi_num);
         }
-        print(env, ", polarity=%u, phase=%u, bits=%u", self->spi->Init.CLKPolarity == SPI_POLARITY_LOW ? 0 : 1, self->spi->Init.CLKPhase == SPI_PHASE_1EDGE ? 1 : 2, self->spi->Init.DataSize == SPI_DATASIZE_8BIT ? 8 : 16);
+        print(env, ", polarity=%u, phase=%u, bits=%u", self->spi->Init.CLKPolarity == SPI_POLARITY_LOW ? 0 : 1, self->spi->Init.CLKPhase == SPI_PHASE_1EDGE ? 0 : 1, self->spi->Init.DataSize == SPI_DATASIZE_8BIT ? 8 : 16);
         if (self->spi->Init.CRCCalculation == SPI_CRCCALCULATION_ENABLED) {
             print(env, ", crc=0x%x", self->spi->Init.CRCPolynomial);
         }
@@ -231,7 +232,7 @@ STATIC void pyb_spi_print(void (*print)(void *env, const char *fmt, ...), void *
     }
 }
 
-/// \method init(mode, baudrate=328125, *, polarity=1, phase=1, bits=8, firstbit=SPI.MSB, ti=False, crc=None)
+/// \method init(mode, baudrate=328125, *, polarity=1, phase=0, bits=8, firstbit=SPI.MSB, ti=False, crc=None)
 ///
 /// Initialise the SPI bus with the given parameters:
 ///
@@ -241,7 +242,7 @@ STATIC const mp_arg_t pyb_spi_init_args[] = {
     { MP_QSTR_mode,     MP_ARG_REQUIRED | MP_ARG_INT, {.u_int = 0} },
     { MP_QSTR_baudrate, MP_ARG_INT, {.u_int = 328125} },
     { MP_QSTR_polarity, MP_ARG_KW_ONLY | MP_ARG_INT,  {.u_int = 1} },
-    { MP_QSTR_phase,    MP_ARG_KW_ONLY | MP_ARG_INT,  {.u_int = 1} },
+    { MP_QSTR_phase,    MP_ARG_KW_ONLY | MP_ARG_INT,  {.u_int = 0} },
     { MP_QSTR_dir,      MP_ARG_KW_ONLY | MP_ARG_INT,  {.u_int = SPI_DIRECTION_2LINES} },
     { MP_QSTR_bits,     MP_ARG_KW_ONLY | MP_ARG_INT,  {.u_int = 8} },
     { MP_QSTR_nss,      MP_ARG_KW_ONLY | MP_ARG_INT,  {.u_int = SPI_NSS_SOFT} },
@@ -281,7 +282,7 @@ STATIC mp_obj_t pyb_spi_init_helper(const pyb_spi_obj_t *self, mp_uint_t n_args,
     else { init->BaudRatePrescaler = SPI_BAUDRATEPRESCALER_256; }
 
     init->CLKPolarity = vals[2].u_int == 0 ? SPI_POLARITY_LOW : SPI_POLARITY_HIGH;
-    init->CLKPhase = vals[3].u_int == 1 ? SPI_PHASE_1EDGE : SPI_PHASE_2EDGE;
+    init->CLKPhase = vals[3].u_int == 0 ? SPI_PHASE_1EDGE : SPI_PHASE_2EDGE;
     init->Direction = vals[4].u_int;
     init->DataSize = (vals[5].u_int == 16) ? SPI_DATASIZE_16BIT : SPI_DATASIZE_8BIT;
     init->NSS = vals[6].u_int;
diff --git a/tests/pyb/spi.py b/tests/pyb/spi.py
index 90dfb441a..24a7a85a5 100644
--- a/tests/pyb/spi.py
+++ b/tests/pyb/spi.py
@@ -5,10 +5,10 @@ print(spi)
 
 spi = SPI(1, SPI.MASTER)
 spi = SPI(1, SPI.MASTER, baudrate=500000)
-spi = SPI(1, SPI.MASTER, 500000, polarity=1, phase=1, bits=8, firstbit=SPI.MSB, ti=False, crc=None)
+spi = SPI(1, SPI.MASTER, 500000, polarity=1, phase=0, bits=8, firstbit=SPI.MSB, ti=False, crc=None)
 print(spi)
 
-spi.init(SPI.SLAVE)
+spi.init(SPI.SLAVE, phase=1)
 print(spi)
 
 spi.init(SPI.MASTER)
diff --git a/tests/pyb/spi.py.exp b/tests/pyb/spi.py.exp
index 030dfe1b3..68ebbcafb 100644
--- a/tests/pyb/spi.py.exp
+++ b/tests/pyb/spi.py.exp
@@ -1,5 +1,5 @@
 SPI(1)
-SPI(1, SPI.MASTER, baudrate=328125, polarity=1, phase=1, bits=8)
+SPI(1, SPI.MASTER, baudrate=328125, polarity=1, phase=0, bits=8)
 SPI(1, SPI.SLAVE, polarity=1, phase=1, bits=8)
 b'\xff'
 b'\xff'