ch552: Use the new hardware CTS signals for UART access

- Use CTS signals to let the FPGA and CH552 signal each other that
    it is OK send UART data.
  - Update the CH552 rx and frame handling logic.
  - Fix minor spelling errors and indentation

hw/usb_interface/ch552_fw/include/debug.c

@@ -137,7 +137,8 @@ void putchar(char c)
     SBUF = c;
 }
 
-char getchar() {
+char getchar(void)
+{
     while(!RI); /* assumes UART is initialized */
     RI = 0;
     return SBUF;
@@ -152,7 +153,8 @@ int putchar(int c)
     return c;
 }
 
-int getchar() {
+int getchar(void)
+{
     while(!RI); /* assumes UART is initialized */
     RI = 0;
     return SBUF;
@@ -198,3 +200,68 @@ void gpio_unset(uint8_t pin)
         break;
     }
 }
+
+uint8_t gpio_get(uint8_t pin)
+{
+    uint8_t ret = 0;
+
+    switch (pin) {
+    case 0x10: // p1.4
+        ret = P1 & 0x10;
+        break;
+    case 0x20: // p1.5
+        ret = P1 & 0x20;
+        break;
+    default: // do nothing, unsupported pin.
+        ret = 0xff;
+        break;
+    }
+
+    return ret;
+}
+
+// Set pin p1.4 to GPIO input mode. (FPGA_CTS)
+void gpio_init_p1_4_in()
+{
+    // p1.4
+    P1_MOD_OC &= ~0x10; // Output Mode: 0 = Push-pull output, 1 = Open-drain output
+    P1_DIR_PU &= ~0x10; // Port Direction Control and Pull-up Enable Register:
+                        //    Push-pull output mode:
+                        //        0 = Input.
+                        //        1 = Output
+                        //    Open-drain output mode:
+                        //        0 = Pull-up resistor disabled
+                        //        1 = Pull-up resistor enabled
+}
+
+// Read status of pin 1.4
+uint8_t gpio_p1_4_get(void)
+{
+    return (P1 & 0x10); // p1.4
+}
+
+// Set pin p1.5 to GPIO output mode. (CH552_CTS)
+void gpio_init_p1_5_out()
+{
+    // p1.5
+    P1_MOD_OC &= ~0x20; // Output Mode: 0 = Push-pull output, 1 = Open-drain output
+    P1_DIR_PU |=  0x20; // Port Direction Control and Pull-up Enable Register:
+                        //    Push-pull output mode:
+                        //        0 = Input.
+                        //        1 = Output
+                        //    Open-drain output mode:
+                        //        0 = Pull-up resistor disabled
+                        //        1 = Pull-up resistor enabled
+}
+
+// Set p1.5 high
+void gpio_p1_5_set(void)
+{
+    P1 |= 0x20; // p1.4
+}
+
+// Set p1.5 low
+void gpio_p1_5_unset(void)
+{
+    P1 &= ~0x20;
+}

hw/usb_interface/ch552_fw/include/debug.h

@@ -38,10 +38,22 @@
 //#define UART1_BAUD    1000000
 #endif
 
-void CfgFsys();            // CH554 clock selection and configuration
+void CfgFsys(void);        // CH554 clock selection and configuration
 void mDelayuS(uint16_t n); // Delay in units of uS
 void mDelaymS(uint16_t n); // Delay in mS
 
+// Set pin p1.4 and p1.5 to GPIO output mode.
+void gpio_init(void);
+void gpio_set(uint8_t pin);
+void gpio_unset(uint8_t pin);
+uint8_t gpio_get(uint8_t pin);
+
+void gpio_init_p1_4_in(void);
+void gpio_init_p1_5_out(void);
+uint8_t gpio_p1_4_get(void);
+void gpio_p1_5_set(void);
+void gpio_p1_5_unset(void);
+
 /*******************************************************************************
  * Function Name  : CH554UART0Alter()
  * Description    : Set the alternate pin mappings for UART0 (RX on P1.2, TX on P1.3)
@@ -83,7 +95,7 @@ inline void mInitSTDIO( )
     }
     TMOD = (TMOD & ~bT1_GATE & ~bT1_CT & ~MASK_T1_MOD) | bT1_M1; // Timer1 as 8-bit auto-reload timer
     T2MOD = T2MOD | bTMR_CLK | bT1_CLK; // Timer1 clock selection
-    TH1 = 0-x;                          // 12MHz crystal oscillator, buad / 12 is the actual need to set the baud rate
+    TH1 = 0-x;                          // 12MHz crystal oscillator, baud / 12 is the actual need to set the baud rate
     TR1 = 1;                            // Start timer 1
     TI = 1;                             // Enable transmit interrupt
     REN = 1;                            // UART0 receive enable
@@ -191,16 +203,18 @@ inline void CH554UART1SendBuffer(uint8_t *Buf, uint32_t Len)
 {
     uint32_t Count = 0;
     while (Count < Len) {
-        SBUF1 = Buf[Count++];
-        while (U1TI == 0)
-            ;
-        U1TI = 0;
+        if (gpio_p1_4_get()) {
+            SBUF1 = Buf[Count++];
+            while (U1TI == 0)
+                ;
+            U1TI = 0;
+        }
     }
 }
 
 #if SDCC < 370
 void putchar(char c);
-char getchar();
+char getchar(void);
 #else
 int putchar(int c);
 int getchar(void);
@@ -243,9 +257,4 @@ inline void CH554WDTFeed(uint8_t tim)
     WDOG_COUNT = tim; // Watchdog counter assignment
 }
 
-// Set pin p1.4 and p1.5 to GPIO output mode.
-void gpio_init();
-void gpio_set(uint8_t pin);
-void gpio_unset(uint8_t pin);
-
 #endif

hw/usb_interface/ch552_fw/include/print.h

@@ -3,7 +3,7 @@
 
 #include <stdint.h>
 
-#define DEBUG_PRINT
+//#define DEBUG_PRINT
 //#define DEBUG_SETUP
 //#define UART_OUT_DEBUG
 //#define USE_NUM_U8