Flush FTDI buffer to avoid 16ms latency timeout and speed up the SPI

Based on the original work of @denis2342 at BusPirate#169 - I have reviewed this commit and believe it is OK. Also improved the ifdef, works fine both for v3 and v4. Co-authored-by: denis2342 <[email protected]> Signed-off-by: Mike Banon <[email protected]>
mikebdp2 · Feb 11, 2024 · 8febbb9 · 8febbb9
1 parent 455d3b6
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diff --git a/Firmware/base.c b/Firmware/base.c
@@ -708,6 +708,9 @@ void user_serial_initialise(void) {
   U1STA = 0x0400;
 
   IFS0bits.U1RXIF = NO;
+
+  /* FTDI CTS setup. */
+  FTDI_CTS_DIR = OUTPUT;
 }
 
 bool user_serial_transmit_done(void) { return U1STAbits.TRMT; }

diff --git a/Firmware/spi.c b/Firmware/spi.c
@@ -942,6 +942,10 @@ void spi_enter_binary_io(void) {
       REPORT_IO_FAILURE();
       break;
     }
+    #ifdef BUSPIRATEV3
+    /* avoid the 16ms FTDI buffer send latency */
+    FTDI_CTS = !FTDI_CTS;
+    #endif /* BUSPIRATEV3 */
   }
 }