Oops - PDI handshake delay was too long, causing the device's /RESET functionality...

diff --git a/Projects/AVRISP-MKII/Lib/XPROG/XPROGTarget.c b/Projects/AVRISP-MKII/Lib/XPROG/XPROGTarget.c
index 0f590c7..843bf5a 100644 (file)
--- a/Projects/AVRISP-MKII/Lib/XPROG/XPROGTarget.c
+++ b/Projects/AVRISP-MKII/Lib/XPROG/XPROGTarget.c
@@ -152,9 +152,11 @@ void XPROGTarget_EnableTargetPDI(void)
        DDRD |=  (1 << 5) | (1 << 3);\r
        DDRD &= ~(1 << 2);\r
        \r
        DDRD |=  (1 << 5) | (1 << 3);\r
        DDRD &= ~(1 << 2);\r
        \r

-       /* Set DATA line high for at least 90ns to disable /RESET functionality */\r
+       /* Set DATA line high for at least 90ns to disable /RESET functionality (note: too long will enable it again,\r
+        * so a fixed number of NOPs are used here */\r

        PORTD |= (1 << 3);\r
        PORTD |= (1 << 3);\r

-       _delay_ms(1);\r
+       asm volatile ("NOP"::);\r
+       asm volatile ("NOP"::);\r

        \r
        /* Set up the synchronous USART for XMEGA communications - \r
           8 data bits, even parity, 2 stop bits */\r
        \r
        /* Set up the synchronous USART for XMEGA communications - \r
           8 data bits, even parity, 2 stop bits */\r


@@ -166,9 +168,11 @@ void XPROGTarget_EnableTargetPDI(void)
        BITBANG_PDIDATA_DDR  |= BITBANG_PDIDATA_MASK;\r
        BITBANG_PDICLOCK_DDR |= BITBANG_PDICLOCK_MASK;\r
        \r
        BITBANG_PDIDATA_DDR  |= BITBANG_PDIDATA_MASK;\r
        BITBANG_PDICLOCK_DDR |= BITBANG_PDICLOCK_MASK;\r
        \r

-       /* Set DATA line high for at least 90ns to disable /RESET functionality */\r
+       /* Set DATA line high for at least 90ns to disable /RESET functionality (note: too long will enable it again,\r
+        * so a fixed number of NOPs are used here */\r

        BITBANG_PDIDATA_PORT |= BITBANG_PDIDATA_MASK;\r
        BITBANG_PDIDATA_PORT |= BITBANG_PDIDATA_MASK;\r

-       _delay_ms(1);\r
+       asm volatile ("NOP"::);\r
+       asm volatile ("NOP"::);\r

 \r
        /* Fire timer compare channel A ISR to manage the software USART */\r
        OCR1A   = BITS_BETWEEN_USART_CLOCKS;\r
 \r
        /* Fire timer compare channel A ISR to manage the software USART */\r
        OCR1A   = BITS_BETWEEN_USART_CLOCKS;\r