S88: added clock frequency setting: 1 .. 250 kHz

traintastic · Aug 28, 2024 · 47148f1 · 47148f1
1 parent aa0bcee
commit 47148f1
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Showing 4 changed files with 23 additions and 21 deletions.
diff --git a/src/s88/s88.cpp b/src/s88/s88.cpp
@@ -32,13 +32,13 @@
 namespace S88 {
 
 static bool g_enabled = false;
+static uint g_offset;
+static pio_sm_config g_config;
 static uint16_t g_inputCount;
 static absolute_time_t g_nextScan;
 static uint g_fifoRead;
 static uint g_inputIndex;
 
-#define CLOCK_FREQUENCY 10000
-
 void init()
 {
   //gpio_init(S88_PIN_POWER);
@@ -52,35 +52,31 @@ void init()
 
   pio_sm_set_consecutive_pindirs(S88_PIO, S88_SM, S88_PIN_CLOCK, 3, true);
 
-  uint offset = pio_add_program(S88_PIO, &s88_program);
-  pio_sm_config c = s88_program_get_default_config(offset);
-
-  sm_config_set_set_pins(&c, S88_PIN_CLOCK, 3);
-  sm_config_set_sideset_pins(&c, S88_PIN_CLOCK);
-  sm_config_set_in_pins(&c, S88_PIN_DATA);
-
-  sm_config_set_out_shift(&c, true, true, 32); // right shift, autopush
+  g_offset = pio_add_program(S88_PIO, &s88_program);
+  g_config = s88_program_get_default_config(g_offset);
 
-  float div = (float)clock_get_hz(clk_sys) / (4 * CLOCK_FREQUENCY);
-  sm_config_set_clkdiv(&c, div);
+  sm_config_set_set_pins(&g_config, S88_PIN_CLOCK, 3);
+  sm_config_set_sideset_pins(&g_config, S88_PIN_CLOCK);
+  sm_config_set_in_pins(&g_config, S88_PIN_DATA);
 
-  pio_sm_init(S88_PIO, S88_SM, offset, &c);
+  sm_config_set_out_shift(&g_config, true, true, 32); // right shift, autopush
 }
 
 bool enabled()
 {
   return g_enabled;
 }
 
-void enable(uint8_t moduleCount)
+void enable(uint8_t moduleCount, uint8_t clockFrequency)
 {
   //gpio_put(S88_PIN_POWER, 1);
 
   pio_sm_set_enabled(S88_PIO, S88_SM, false);
 
-  pio_sm_clear_fifos(S88_PIO, S88_SM);
+  const float div = (float)clock_get_hz(clk_sys) / (4 * clockFrequency * 1000);
+  sm_config_set_clkdiv(&g_config, div);
 
-  pio_sm_restart(S88_PIO, S88_SM);
+  pio_sm_init(S88_PIO, S88_SM, g_offset, &g_config);
 
   pio_sm_set_enabled(S88_PIO, S88_SM, true);
 

diff --git a/src/s88/s88.hpp b/src/s88/s88.hpp
@@ -28,10 +28,12 @@ namespace S88 {
 
 constexpr uint8_t moduleCountMin = 1;
 constexpr uint8_t moduleCountMax = 16;
+constexpr uint8_t clockFrequencyMin = 1; // kHz
+constexpr uint8_t clockFrequencyMax = 250; // kHz
 
 void init();
 bool enabled();
-void enable(uint8_t moduleCount);
+void enable(uint8_t moduleCount, uint8_t clockFrequency);
 void disable();
 void process();
 

diff --git a/src/traintasticcs/messages.hpp b/src/traintasticcs/messages.hpp
@@ -181,12 +181,14 @@ struct InitXpressNetOk : MessageNoData
 struct InitS88 : Message
 {
   uint8_t moduleCount;
+  uint8_t clockFrequency;
   Checksum checksum;
 
-  constexpr InitS88(uint8_t moduleCount_)
+  constexpr InitS88(uint8_t moduleCount_, uint8_t clockFrequency_)
     : Message(Command::InitS88, sizeof(InitS88) - sizeof(Message) - sizeof(checksum))
     , moduleCount{moduleCount_}
-    , checksum{static_cast<Checksum>(static_cast<uint8_t>(command) ^ length ^ moduleCount)}
+    , clockFrequency{clockFrequency_}
+    , checksum{static_cast<Checksum>(static_cast<uint8_t>(command) ^ length ^ moduleCount ^ clockFrequency)}
   {
   }
 };

diff --git a/src/traintasticcs/traintasticcs.cpp b/src/traintasticcs/traintasticcs.cpp
@@ -129,15 +129,17 @@ static void received()
       const auto& initS88 = static_cast<const InitS88&>(message);
       if(message.size() != sizeof(InitS88) ||
           initS88.moduleCount < S88::moduleCountMin ||
-          initS88.moduleCount > S88::moduleCountMax)
+          initS88.moduleCount > S88::moduleCountMax ||
+          initS88.clockFrequency < S88::clockFrequencyMin ||
+          initS88.clockFrequency > S88::clockFrequencyMax)
       {
         return send(Error(message.command, ErrorCode::InvalidCommandPayload));
       }
       if(S88::enabled())
       {
         return send(Error(message.command, ErrorCode::AlreadyInitialized));
       }
-      S88::enable(initS88.moduleCount);
+      S88::enable(initS88.moduleCount, initS88.clockFrequency);
       return send(InitS88Ok());
     }
   }