Minor documentation improvements.

[pub/USBasp.git] / Projects / AVRISP-MKII / Lib / XPROG / XPROGTarget.c

diff --git a/Projects/AVRISP-MKII/Lib/XPROG/XPROGTarget.c b/Projects/AVRISP-MKII/Lib/XPROG/XPROGTarget.c
index f0ef2b6..5ea9404 100644 (file)
--- a/Projects/AVRISP-MKII/Lib/XPROG/XPROGTarget.c
+++ b/Projects/AVRISP-MKII/Lib/XPROG/XPROGTarget.c
@@ -1,13 +1,13 @@
 /*
              LUFA Library
-     Copyright (C) Dean Camera, 2010.
+     Copyright (C) Dean Camera, 2012.
 
   dean [at] fourwalledcubicle [dot] com
            www.lufa-lib.org
 */
 
 /*
-  Copyright 2010  Dean Camera (dean [at] fourwalledcubicle [dot] com)
+  Copyright 2012  Dean Camera (dean [at] fourwalledcubicle [dot] com)
 
   Permission to use, copy, modify, distribute, and sell this
   software and its documentation for any purpose is hereby granted
@@ -39,7 +39,7 @@
 #if defined(ENABLE_XPROG_PROTOCOL) || defined(__DOXYGEN__)
 
 /** Flag to indicate if the USART is currently in Tx or Rx mode. */
-volatile bool IsSending;
+bool IsSending;
 
 /** Enables the target's PDI interface, holding the target in reset until PDI mode is exited. */
 void XPROGTarget_EnableTargetPDI(void)
@@ -55,13 +55,13 @@ void XPROGTarget_EnableTargetPDI(void)
        _delay_us(1);
 
        /* Set up the synchronous USART for XMEGA communications - 8 data bits, even parity, 2 stop bits */
-       UBRR1  = (F_CPU / XPROG_HARDWARE_SPEED);
+       UBRR1  = ((F_CPU / 2 / XPROG_HARDWARE_SPEED) - 1);
        UCSR1B = (1 << TXEN1);
        UCSR1C = (1 << UMSEL10) | (1 << UPM11) | (1 << USBS1) | (1 << UCSZ11) | (1 << UCSZ10) | (1 << UCPOL1);
 
-       /* Send two BREAKs of 12 bits each to enable PDI interface (need at least 16 idle bits) */
-       XPROGTarget_SendBreak();
-       XPROGTarget_SendBreak();
+       /* Send two IDLEs of 12 bits each to enable PDI interface (need at least 16 idle bits) */
+       XPROGTarget_SendIdle();
+       XPROGTarget_SendIdle();
 }
 
 /** Enables the target's TPI interface, holding the target in reset until TPI mode is exited. */
@@ -78,21 +78,22 @@ void XPROGTarget_EnableTargetTPI(void)
        DDRD |=  (1 << 5) | (1 << 3);
        DDRD &= ~(1 << 2);
 
-       /* Set up the synchronous USART for TINY communications - 8 data bits, even parity, 2 stop bits */
-       UBRR1  = (F_CPU / XPROG_HARDWARE_SPEED);
+       /* Set up the synchronous USART for TPI communications - 8 data bits, even parity, 2 stop bits */
+       UBRR1  = ((F_CPU / 2 / XPROG_HARDWARE_SPEED) - 1);
        UCSR1B = (1 << TXEN1);
        UCSR1C = (1 << UMSEL10) | (1 << UPM11) | (1 << USBS1) | (1 << UCSZ11) | (1 << UCSZ10) | (1 << UCPOL1);
 
-       /* Send two BREAKs of 12 bits each to enable TPI interface (need at least 16 idle bits) */
-       XPROGTarget_SendBreak();
-       XPROGTarget_SendBreak();
+       /* Send two IDLEs of 12 bits each to enable TPI interface (need at least 16 idle bits) */
+       XPROGTarget_SendIdle();
+       XPROGTarget_SendIdle();
 }
 
 /** Disables the target's PDI interface, exits programming mode and starts the target's application. */
 void XPROGTarget_DisableTargetPDI(void)
 {
        /* Switch to Rx mode to ensure that all pending transmissions are complete */
-       XPROGTarget_SetRxMode();
+       if (IsSending)
+         XPROGTarget_SetRxMode();
 
        /* Turn off receiver and transmitter of the USART, clear settings */
        UCSR1A  = ((1 << TXC1) | (1 << RXC1));
@@ -108,14 +109,15 @@ void XPROGTarget_DisableTargetPDI(void)
 void XPROGTarget_DisableTargetTPI(void)
 {
        /* Switch to Rx mode to ensure that all pending transmissions are complete */
-       XPROGTarget_SetRxMode();
+       if (IsSending)
+         XPROGTarget_SetRxMode();
 
        /* Turn off receiver and transmitter of the USART, clear settings */
        UCSR1A |= (1 << TXC1) | (1 << RXC1);
        UCSR1B  = 0;
        UCSR1C  = 0;
 
-       /* Set all USART lines as input, tristate */
+       /* Set all USART lines as inputs, tristate */
        DDRD  &= ~((1 << 5) | (1 << 3));
        PORTD &= ~((1 << 5) | (1 << 3) | (1 << 2));
 
@@ -140,7 +142,7 @@ void XPROGTarget_SendByte(const uint8_t Byte)
        UDR1    = Byte;
 }
 
-/** Receives a byte via the software USART, blocking until data is received.
+/** Receives a byte via the hardware USART, blocking until data is received or timeout expired.
  *
  *  \return Received byte from the USART
  */
@@ -156,19 +158,20 @@ uint8_t XPROGTarget_ReceiveByte(void)
        return UDR1;
 }
 
-/** Sends a BREAK via the USART to the attached target, consisting of a full frame of idle bits. */
-void XPROGTarget_SendBreak(void)
+/** Sends an IDLE via the USART to the attached target, consisting of a full frame of idle bits. */
+void XPROGTarget_SendIdle(void)
 {
        /* Switch to Tx mode if currently in Rx mode */
        if (!(IsSending))
          XPROGTarget_SetTxMode();
 
-       /* Need to do nothing for a full frame to send a BREAK */
+       /* Need to do nothing for a full frame to send an IDLE */
        for (uint8_t i = 0; i < BITS_IN_USART_FRAME; i++)
        {
                /* Wait for a full cycle of the clock */
                while (PIND & (1 << 5));
                while (!(PIND & (1 << 5)));
+               while (PIND & (1 << 5));
        }
 }
 
@@ -177,6 +180,7 @@ static void XPROGTarget_SetTxMode(void)
        /* Wait for a full cycle of the clock */
        while (PIND & (1 << 5));
        while (!(PIND & (1 << 5)));
+       while (PIND & (1 << 5));
 
        PORTD  |=  (1 << 3);
        DDRD   |=  (1 << 3);