Merge branch 'main' into XCVR

docs/assembly.md

@@ -1,66 +1,5 @@
 # Assembly
 
-## Before you start
+Instructions have moved to the wiki
 
-Read through all instructions before starting.
-
-## Videos
-
-The community has created a few assembly videos:
-* [Stephen Arsenault - BlueSCSI Kit Assembly](https://www.youtube.com/watch?v=G6lwCfLQwd8) 2:52
-* [Joe's Computer Museum - A New Challenger - BlueSCSI - #MARCHintosh Review](https://www.youtube.com/watch?v=d_8VVmvvlNI) 26:52
-* [Geeky Bit - Tutorial - BlueSCSI Assembly](https://www.youtube.com/watch?v=-nF9FYFgVHM) 20:35
-
-## Building
-
-1. Solder on the surface mount SD Card holder. Use the [Drag Solder](https://youtu.be/Z_KL4fWOMug) technique.
-    - Once on, check continuity of all connections. Fixing this after the BluePill is on will be difficult.
-    - Ensure the SD card fits and you dont have too much solder on the sides or contacts
-2. Solder the diodes to the **bottom** of the board. Be sure they are flush as possible to the bottom.
-![Diode Orientation](images/diodes.png)
-3. Solder the header pins on to the BluePill. Then BluePill pill to the BlueSCSI PCB.
-    - Correct orientation is having the USB connector of the BluePill should be over the SD Card holder.
-    - **NOTE**: Consider adding headers to the board if you would like to have the BluePill removable.
-4. Solder on the resistor nets. Pin one is marked on the board and the resistors.
-   - 220 RNETS (`RN1` & `RN3`) are closest to the BluePill
-     - **NOTE** PIN one on each - they are opposite of eachtoher. See photo.
-   - 330 RNETS (`RN2` & `RN4`) are furthest from the BluePill
-     - **NOTE** PIN one on each - they are opposite of eachtoher. See photo.
-![Orientation RNETs and BluePill](images/orientation.png)
-5. Solder on the Termination Jumpers & place the jumpers on to enable Termiation
-6. Solder the 50 Pin headers on.
-   1. Note Pin 1 and Box header on the silk screen.
-7. Optional - Solder on the berg connector. Only needed if your machine does not supply enough power via the SCSI bus.
-8. Optional - Solder on the debug headers near the SD card. Only nessissarry if re-programming.
-
-### Fully Assembled
-![Fully Assembled](images/assembled.png)
-
-### Version 1.0-b & 1.0-c BOM
-
-#### Mouser Cart
-
-https://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=c5cc83feff
-
-#### Parts
-
-STM32F103C8T6 (U1) aka BluePill board. Beware of fake/scams. Look for reviews. Amazon, ebay, etc.
-
-* 2x 330 (RN2, RN4) Resistor nets https://www.mouser.com/ProductDetail/652-4610X-1LF-330
-
-* 2x 220 (RN1, RN3) Resistor nets https://www.mouser.com/ProductDetail/652-4610X-1LF-220
-
-* 2x Diodes https://www.mouser.com/ProductDetail/583-1N5818-T
-
-* SD Card Holder (J1)  https://www.mouser.com/ProductDetail/538-104031-0811
-
-* Headers https://www.mouser.com/ProductDetail/872-920-0011-01
-
-* 50 PIN SCSI header https://www.mouser.com/ProductDetail/517-30350-6002/
-  - May substitute with 2 rows of headers from above.
-  - **Note on Right angle connectors** - it appears Right angle headers are notched differently then the pin out. Be sure to note PIN 1/red stripe on the cable match up.
-
-### Optional
-
-Floppy/Berg Power header https://www.mouser.com/ProductDetail/571-1718254
-  - Required if your machine does not supply power via TERM POWER. For example a Mac Plus or Mac with a Analog/PSU board that has not been recapped.
+https://github.com/erichelgeson/BlueSCSI/wiki/Assembly

src/BlueSCSI.cpp

@@ -1010,14 +1010,16 @@ void readDataLoop(uint32_t blockSize, byte* dstptr)
   register gpio_reg_map *port_b = PBREG;
   register volatile uint32_t *port_a_idr = &(GPIOA->regs->IDR);
   REQ_ON();
-  // Start of the do/while and WAIT are already aligned to 8 bytes.
+  // Fastest alignment obtained by trial and error.
+  // Wait loop is within an 8 byte prefetch buffer.
+  asm("nop");
   do {
     WAIT_ACK_ACTIVE();
     uint32_t ret = port_b->IDR;
     REQ_OFF();
     *dstptr++ = ~(ret >> 8);
     // Move wait loop in to a single 8 byte prefetch buffer
-    asm("nop.w;nop");
+    asm("nop;nop;nop");
     WAIT_ACK_INACTIVE();
     REQ_ON();
     // Extra 1 cycle delay