Reorder bus phase change and file.seek() so that file.seek() acts as …

…a bus settle delay.
androda · Apr 7, 2022 · 916e0e6 · 916e0e6
1 parent 0a12c2c
commit 916e0e6
Showing 1 changed file with 12 additions and 7 deletions.
diff --git a/F4_BlueSCSI/F4_BlueSCSI.ino b/F4_BlueSCSI/F4_BlueSCSI.ino
@@ -922,12 +922,13 @@ void writeDataLoop(uint32_t blocksize)
 void writeDataPhaseSD(uint32_t adds, uint32_t len)
 {
   LOGN("DATAIN PHASE(SD)");
-  uint32_t pos = adds * m_img->m_blocksize;
-  m_img->m_file.seek(pos);
-
   SCSI_OUT(vMSG,inactive) //  gpio_write(MSG, low);
   SCSI_OUT(vCD ,inactive) //  gpio_write(CD, low);
   SCSI_OUT(vIO ,  active) //  gpio_write(IO, high);
+  //Bus settle delay 400ns, file.seek() measured at over 1000ns.
+
+  uint32_t pos = adds * m_img->m_blocksize;
+  m_img->m_file.seek(pos);
 
   SCSI_DB_OUTPUT()
   for(uint32_t i = 0; i < len; i++) {
@@ -1011,11 +1012,13 @@ void readDataLoop(uint32_t blockSize)
 void readDataPhaseSD(uint32_t adds, uint32_t len)
 {
   LOGN("DATAOUT PHASE(SD)");
-  uint32_t pos = adds * m_img->m_blocksize;
-  m_img->m_file.seek(pos);
   SCSI_OUT(vMSG,inactive) //  gpio_write(MSG, low);
   SCSI_OUT(vCD ,inactive) //  gpio_write(CD, low);
   SCSI_OUT(vIO ,inactive) //  gpio_write(IO, low);
+  //Bus settle delay 400ns, file.seek() measured at over 1000ns.
+
+  uint32_t pos = adds * m_img->m_blocksize;
+  m_img->m_file.seek(pos);
   for(uint32_t i = 0; i < len; i++) {
     m_resetJmp = true;
 #if WRITE_SPEED_OPTIMIZE
@@ -1043,11 +1046,13 @@ void readDataPhaseSD(uint32_t adds, uint32_t len)
 void verifyDataPhaseSD(uint32_t adds, uint32_t len)
 {
   LOGN("DATAOUT PHASE(SD)");
-  uint32_t pos = adds * m_img->m_blocksize;
-  m_img->m_file.seek(pos);
   SCSI_OUT(vMSG,inactive) //  gpio_write(MSG, low);
   SCSI_OUT(vCD ,inactive) //  gpio_write(CD, low);
   SCSI_OUT(vIO ,inactive) //  gpio_write(IO, low);
+  //Bus settle delay 400ns, file.seek() measured at over 1000ns.
+
+  uint32_t pos = adds * m_img->m_blocksize;
+  m_img->m_file.seek(pos);
   for(uint32_t i = 0; i < len; i++) {
 #if WRITE_SPEED_OPTIMIZE
     readDataLoop(m_img->m_blocksize);