client sdcard test

demos/sdcard/apple1_sdcard/apple1_sdcard.ino

@@ -11,44 +11,59 @@
 #define D6 7   /* I/O data bit 6, connects to PA6 on the VIA */
 #define D7 8   /* I/O data bit 7, connects to PA7 on the VIA */
 
-#define CPU_CLOCK   9   /* cpu send data clock, VIA.PB0 => MCU */  
-#define MCU_CLOCK  10   /* mcu send data clock, VIA.PB1 <= MCU */
+#define CPU_STROBE   9   /* PB0 => MCU  1=cpu byte is available on the data port; 0 cpu is waiting */  
+#define MCU_STROBE  10   /* PB1 <= MCU  1=mcu byte is available on the data port; 0 mcu is waiting */
 
-// utility function for read a bit 
-#define BIT(data,n) (((data) >> (n)) & 1)
+// indicates that a timeout occurred during wait()
+int TIMEOUT = 0;
 
 void setup() {
   // debug on serial
   Serial.begin(9600);  
+    
+  pinMode(CPU_STROBE, INPUT);
+  pinMode(MCU_STROBE, OUTPUT);
   
-  pinMode(CPU_CLOCK, INPUT);
-  pinMode(MCU_CLOCK, OUTPUT);
+  digitalWrite(MCU_STROBE, LOW);   
 }
 
 void loop() {
   // applicazione di esempio: manda un messaggio quando riceve il comando 42
+  TIMEOUT = 0;
+
   int data = receive_byte_from_cpu();
 
-  if(data == 42) {
+  if(data == 42 && !TIMEOUT) {
+    
     Serial.println("command 42 received from CPU");
     char *msg = "HELLO WORLD!\r\n";
     for(int t=0; t<strlen(msg); t++) {
       send_byte_to_cpu(msg[t]);  
     }      
     send_byte_to_cpu(0);  // terminatore stringa
-    Serial.println("message sento to CPU");
+    if(!TIMEOUT) Serial.println("message sent to CPU");
+    else Serial.println("timeout during send to CPU");
   }  
 }
 
 void wait(int pin, int value) {
-  // TODO prevedere un meccanismo di timeout?
-  while(digitalRead(pin) != value);  
+    
+  unsigned long start_time = millis();  
+  unsigned long elapsed;  
+
+  if(TIMEOUT) break;
+  
+  while(digitalRead(pin) != value) {
+    elapsed = millis() - start_time;
+    if(elapsed > 500) {
+      TIMEOUT = 1;
+      break;
+    }      
+  }
 }
 
-void receive_byte_from_cpu() {
-  
-  // when here, both CPU_CLOCK and MCU_CLOCK are LOW
-  
+int receive_byte_from_cpu() {
+      
   // set data port as input
   pinMode(D0, INPUT);
   pinMode(D1, INPUT);
@@ -57,14 +72,13 @@ void receive_byte_from_cpu() {
   pinMode(D4, INPUT);
   pinMode(D5, INPUT);
   pinMode(D6, INPUT);
-  pinMode(D7, INPUT);
-  
-  // tells CPU we are ready to receive
-  digitalWrite(MCU_CLOCK, HIGH);   
-  
-  // wait data to be signaled as "ready" on the CPU  
-  wait(CPU_CLOCK, HIGH);           
+  pinMode(D7, INPUT);  
 
+  // both strobes are 0   
+  
+  // CPU deposits data byte and sets strobe high
+  wait(CPU_STROBE, HIGH);           
+  
   // read the data byte
   int data = 
     (digitalRead(D0) << 0) |
@@ -76,23 +90,19 @@ void receive_byte_from_cpu() {
     (digitalRead(D6) << 6) |
     (digitalRead(D7) << 7);
 
-  // tells CPU data was received
-  digitalWrite(MCU_CLOCK, HIGH);
-  
-  // wait the CPU to end operation
-  wait(CPU_CLOCK, LOW);           
-  
-  // we also terminate
-  digitalWrite(MCU_CLOCK, LOW);
-  
-  // when here, both CPU_CLOCK and MCU_CLOCK are LOW
-  
-  return byte;
+  // after reading the byte, MCU sets strobe high
+  digitalWrite(MCU_STROBE, HIGH);
+
+  // CPU now sets strobe low
+  wait(CPU_STROBE, LOW);
+
+  // and MCU sets strobe low
+  digitalWrite(MCU_STROBE, LOW);
+    
+  return data;
 }
 
 void send_byte_to_cpu(int data) {
-
-  // when here, both CPU_CLOCK and MCU_CLOCK are LOW
   
   // set data port as output
   pinMode(D0, OUTPUT);
@@ -103,31 +113,28 @@ void send_byte_to_cpu(int data) {
   pinMode(D5, OUTPUT);
   pinMode(D6, OUTPUT);
   pinMode(D7, OUTPUT);
-  
-  // wait until CPU is ready to receive (should be already)
-  wait(CPU_CLOCK, LOW);
 
-  // put byte on D0-D7
-  digitalWrite(D0, BIT(data,0) );
-  digitalWrite(D1, BIT(data,1) );
-  digitalWrite(D2, BIT(data,2) );
-  digitalWrite(D3, BIT(data,3) );
-  digitalWrite(D4, BIT(data,4) );
-  digitalWrite(D5, BIT(data,5) );
-  digitalWrite(D6, BIT(data,6) );
-  digitalWrite(D7, BIT(data,7) );
+  // both strobes are 0
   
-  // tells CPU byte is ready on the data port
-  digitalWrite(MCU_CLOCK, HIGH);
+  // put byte on the data port
+  digitalWrite(D0, data &   1);
+  digitalWrite(D1, data &   2);
+  digitalWrite(D2, data &   4);
+  digitalWrite(D3, data &   8);
+  digitalWrite(D4, data &  16);
+  digitalWrite(D5, data &  32);
+  digitalWrite(D6, data &  64);
+  digitalWrite(D7, data & 128);
   
-  // wait for CPU to read the data
-  wait(CPU_CLOCK, HIGH);
+  // after depositing data byte, MCU sets strobe high
+  digitalWrite(MCU_STROBE, HIGH);
+  
+  // wait for CPU to set strobe high
+  wait(CPU_STROBE, HIGH);  
   
   // tells CPU byte we are finished
-  digitalWrite(MCU_CLOCK, LOW);
-  
-  // wait for CPU end as well
-  wait(CPU_CLOCK, LOW);
-  
-  // when here, both CPU_CLOCK and MCU_CLOCK are LOW    
+  digitalWrite(MCU_STROBE, LOW); 
+
+  // wait for CPU to set strobe low
+  wait(CPU_STROBE, LOW);  
 }

demos/sdcard/m.bat

@@ -0,0 +1 @@
+call ..\..\tools\build sdcard

demos/sdcard/sdcard.c

@@ -0,0 +1,95 @@
+#include <utils.h>
+#include <apple1.h>
+
+byte *const PORTB = (byte *) 0xA000;  // port B register
+byte *const PORTA = (byte *) 0xA001;  // port A register
+byte *const DDRB  = (byte *) 0xA002;  // port A data direction register
+byte *const DDRA  = (byte *) 0xA003;  // port B data direction register
+
+#define CPU_STROBE(v) (*PORTB = (v))  /* CPU strobe is bit 0 OUTPUT */
+#define MCU_STROBE    (*PORTB & 128)  /* MCU strobe is bit 7 INPUT  */
+
+byte TIMEOUT = 0;
+
+void wait_mcu_strobe(byte v) {   
+   if(TIMEOUT) return;
+
+   unsigned int time = 0;
+   while((v==0 && MCU_STROBE != 0) || (v!=0 && MCU_STROBE == 0)) {
+      time++;
+      if(time > 5000) {
+         TIMEOUT = 1;
+         return;
+      }  
+   }
+}
+
+void send_byte_to_MCU(byte data) {   
+   *DDRA = 0xFF;        // set port A as output   
+   *PORTA = data;       // deposit byte on the data port   
+   CPU_STROBE(1);       // set strobe high   
+   wait_mcu_strobe(1);  // wait for the MCU to read the data   
+   CPU_STROBE(0);       // set strobe low   
+   wait_mcu_strobe(0);  // wait for the MCU to set strobe low
+}
+
+byte receive_byte_from_MCU() {
+   *DDRA = 0;          // set port A as input
+   CPU_STROBE(0);      // set listen
+   wait_mcu_strobe(1); // wait for the MCU to deposit data
+   byte data = *PORTA; // read data
+   CPU_STROBE(1);      // set strobe high
+   wait_mcu_strobe(0); // wait for the MCU to set strobe low
+   CPU_STROBE(0);      // set strobe low
+   return data;
+}
+
+void VIA_init() {
+   *DDRB = 1;       // pin 1 is output (CPU_STROBE), pin7 is input (MCU_STROBE)
+   CPU_STROBE(0);   // initial state
+}
+
+void messagio_test() {
+   
+   TIMEOUT = 0;           // resetta il timeout
+   send_byte_to_MCU(42);  // manda il comando 42
+
+   if(TIMEOUT) {
+      woz_puts("\rTIMEOUT\r");            
+      return;
+   }
+
+   // legge la stringa di ritorno
+   while(1) {
+      byte data = receive_byte_from_MCU();
+      if(TIMEOUT) {
+         woz_puts("\rTIMEOUT\r");
+         break;
+      }
+      if(data == 0) break;  // end of string
+      woz_putc(data);
+   }
+}
+
+void main() {   
+
+   VIA_init();
+
+   woz_puts("\rMCU TEST\r\r");
+   woz_puts("[4] SEND 42 TO MCU\r");
+   woz_puts("[0] EXIT\r");
+
+   byte data;
+
+   // loop continuo
+   while(1) {
+      byte key = apple1_getkey();
+
+           if(key == '4') messagio_test();         
+      else if(key == '0') {
+         woz_puts("BYE\r");
+         woz_mon();
+      }
+   }
+}
+