-# ULX3S JTAG Connection with STLINKV2
+# ULX3S JTAG Connection with ft232r
+
+Note: this page is for connecting a *secondary* JTAG connection to
+the Libre-SOC Core, in order to test the actual HDL implementation
+of JTAG. "Normal" JTAG documentation instructs you how to connect
+to the **FPGA** hard-macro JTAG port (in some fashion). Whilst the
+FPGA has a JTAG port as a hard-macro these instructions do **not**
+apply to that: they apply **specifically** to actual implementation
+in HDL of a JTAG TAP interface suitable for deployment on an ASIC,
+and, consequently, in order to test that, four GPIO pads had to be
+picked to bring those signals out. These instructions describe how
+to correctly wire up an FT232r to connect to those four GPIO pads.
Cross referenced with:
<http://lists.libre-soc.org/pipermail/libre-soc-dev/2020-October/000873.html>
+<https://www.amazon.co.uk/DSD-TECH-adapter-FT232RL-Compatible/dp/B07BBPX8B8/ref=sr_1_11?dchild=1&keywords=ft232&qid=1632498288&s=amazon-devices&sr=1-11>
+
+<https://www.amazon.co.uk/Elegoo-120pcs-Multicolored-Breadboard-arduino-colorful/dp/B01EV70C78/>
+
## Original Instructions
-lkcl:
-
-
-> the JTAG TAP interface on the *FPGA* is hard-coded silicon.
-
-> the JTAG TAP interface connected on the processor and soft-implemented
-> *by* the FPGA is likely completely inaccessible until someone
-> allocates pins to "jtag_tdi/tdo/tms/tck" in the litex config.
->
-> which means: someone's going to have to to through this file:
-> <https://github.com/enjoy-digital/litex/blob/master/litex/boards/platforms/ulx3s.py#L72>
-> (which defines the pin allocations)
->
-> and in this file do some Voodoo Magic on this file's TestSoC:
-> <https://git.libre-soc.org/?p=soc.git;a=blob;f=src/soc/litex/florent/ulx3s85f.py;hb=HEAD>
->
-> similar to these four lines:
-> <https://git.libre-soc.org/?p=soc.git;a=blob;f=src/soc/litex/florent/ls180soc.py;h=4279effcffe2fbf15f877e9b2a1b76beab248dac;hb=HEAD#l460>
->
-> but instead doing something like... err....
->
-> gpio0_pads = platform.reqiest("gpio", 0) # because back in ulx3s.py there's gpio 0, 1, and 2
->
-> self.comb += self.cpu.jtag_tck.eq(gpio0_pads.p) # because again back in that file there are 2 pins, one named "p", one named "n"
->
-> self.comb += self.cpu.jtag_tms.eq(gpio0_pads.n) # etc.
->
-> and then request gpio1 for the other 2 pins
->
-> theeeen you'll need to go back to that ulx3s.py litex platform file,
-> look up the pin names B11, C11, A10, A11, and find out what the hell
-> they are, whether they're suitable for use.
->
-> if they are, then great! these are what you wire up the STLINKv2 to,
-> according to what you decided to connect to just above.
->
-> but for god's sake do not get this wrong, such as driving an input as
-> an output or vice-versa, or wiring up 5.0V to GND with those
-> jumper-cables.
->
-> do *NOT* randomly upload and power up the ulx3s until this has been
-> THOROUGHLY triple-checked. or, you are entirely free to not bother
-> and to end up learning the hard way by destroying the FPGA.
+See <https://bugs.libre-soc.org/show_bug.cgi?id=517#c0>
+
+Checklist based on above
+
+* For god's sake make sure you get this right, ***TRIPLE*** check everything.
+
+* ***DO*** make sure to ***only*** drive an input as an input, and to ***only*** drive an output as an output.
+
+* ***DO*** make sure to ***only*** wire up 3.3V to 3.3V and to ***only*** wire up GND to GND with the jumper-cables.
+
+* ***DO*** make sure that ***before*** even ***thinking*** of uploading to and powering up the FPGA that everything has been ***THOROUGHLY*** triple-checked.
+
+If you violate any of the above stated hard-and-fast rules you will end up learning the hard way by **DESTROYING** the FPGA.
+
+To start we have to ensure we have a safe set up.
+
+| Checklist Step |
+|----------------|
+| Ensure power is disconnected from FPGA |
+| Ensure ft232r USB is disconnected |
+| Ensure FPGA USB is disconnected |
+
+Now lets review all of the relevant material on this page before we begin the wiring process.
+
+| Checklist Step |
+|----------------|
+| Review the ft232r Connector diagram and table |
+| Review the connections table for your model of fpga |
+| Ensure the orientation of the FPGA and ft232r match that of the images and diagrams on this page |
+
+Next we will wire up the ft232r and our FPGA in three separate stages.
+
+* First we will attach one end of a ***MALE-TO-MALE (MTM)*** jumper cable to each necessary female header pin-hole on the ft232f.
+
+* Then we will attach one end of a ***FEMALE-TO-FEMALE (FTF)*** cable to each male header pin on the FPGA.
+
+* Finally, we will connect the wires from the ft232r to the wires from the FPGA by matching the colours of the wires.
+
+This way you do not lose the connections when you want to disconnect and store the two devices. We are using FEMALE-TO-FEMALE jumper cables on the male header pins of the FPGA so that the wires do not randomly damage the bare PCB due to a short.
+
+We will wire each of the pins on the the ft232r according to the diagrams, tables, and images on this page.
+
+| Action | Colour | Pin Name |
+|------------|--------|----------|
+| Attach MTM | Black | GND |
+| Attach MTM | Brown | TMS |
+| Attach MTM | Red | VCC |
+| Attach MTM | Orange | TCK |
+| Attach MTM | Yellow | TDI |
+| Attach MTM | Green | TDO |
+
+Next, we will wire each of the pins on the the FPGA according to the diagrams, tables, and images on this page.
+
+Follow this section if you have the ULX3S FPGA:
+
+| Action | Colour | Pin # | Pin Name |
+|------------|--------|-------|----------|
+| Attach FTF | Red | 2 | VREF |
+| Attach FTF | Black | 4 | GND |
+| Attach FTF | Yellow | 5 | TDI |
+| Attach FTF | Brown | 6 | TMS |
+| Attach FTF | Orange | 7 | TCK |
+| Attach FTF | Green | 8 | TDO |
+
+Follow this section if you have the Versa ECP5 FPGA:
+
+| Action | Colour | X3 Pin # | Pin Name |
+|------------|--------|----------|----------|
+| Attach FTF | Red | 39 | VREF |
+| Attach FTF | Black | 1 | GND |
+| Attach FTF | Yellow | 4 | TDI |
+| Attach FTF | Brown | 5 | TMS |
+| Attach FTF | Orange | 6 | TCK |
+| Attach FTF | Green | 7 | TDO |
+
+Final steps for both FPGA boards:
+
+| Checklist Step |
+|----------------|
+| Check each jumper wire connection between the corresponding pins on the FPGA and the ft232r **THREE** times |
+| ***lckl*** check for ground loops? |
+
+
+Finally, we will connect the jumper cables of the same colour from ft232r and the FPGA.
+
+| Checklist Step |
+|----------------|
+| Attach the ends of the **RED** jumper cables |
+| Attach the ends of the **BLACK** jumper cables |
+| Attach the ends of the **YELLOW** jumper cables |
+| Attach the ends of the **BROWN** jumper cables |
+| Attach the ends of the **ORANGE** jumper cables |
+| Attach the ends of the **GREEN** jumper cables |
+
+***lckl if both the micro-usb cable and the ft232r GND and VCC wires are connected to the fpga will this result in volatage fighting where the fpga will be damaged?***
+
+Finally, plug in the USB end of the USB-to-MicroUSB cable that is plugged into the ft232r into your computer. Begin testing the SOC on the FPGA (instructions to follow).
## Connecting the dots:
Accurate render of board for reference <https://github.com/emard/ulx3s/blob/master/pic/ulx3st.jpg>
-STLINKV2 Pins and JTAG signals schematic/user guide <https://www.st.com/resource/en/user_manual/dm00026748-stlinkv2-incircuit-debuggerprogrammer-for-stm8-and-stm32-stmicroelectronics.pdf>
-
Litex platform file <https://github.com/litex-hub/litex-boards/blob/master/litex_boards/platforms/ulx3s.py>
("gpio", 0,
As noted in the schematic pins GP,GN 0-7 are single ended non-differential pairs, whereas pins GP,GN 8-13 I haven't mapped out here as they are bidirectional differential pairs.
-Proposed FPGA External Pin to STLINK JTAG pin connections:
+``` from http://openocd.org/doc/html/Debug-Adapter-Configuration.html#index-ftdi
+List of connections (default physical pin numbers for FT232R in 28-pin SSOP package):
+
+ - RXD(5) - TDI
+ - TXD(1) - TCK
+ - RTS(3) - TDO
+ - CTS(11) - TMS
+ - DTR(2) - TRST
+ - DCD(10) - SRST
+```
+
+``` from https://github.com/ntfreak/openocd/blob/master/src/jtag/drivers/ft232r.c#L79-L99
+/**
+ * FT232R GPIO bit number to RS232 name
+ */
+#define FT232R_BIT_COUNT 8
+static char *ft232r_bit_name_array[FT232R_BIT_COUNT] = {
+ "TXD", /* 0: pin 1 TCK output */
+ "RXD", /* 1: pin 5 TDI output */
+ "RTS", /* 2: pin 3 TDO input */
+ "CTS", /* 3: pin 11 TMS output */
+ "DTR", /* 4: pin 2 /TRST output */
+ "DSR", /* 5: pin 9 unused */
+ "DCD", /* 6: pin 10 /SYSRST output */
+ "RI" /* 7: pin 6 unused */
+};
+
+static int tck_gpio; /* initialized to 0 by default */
+static int tdi_gpio = 1;
+static int tdo_gpio = 2;
+static int tms_gpio = 3;
+static int ntrst_gpio = 4;
+static int nsysrst_gpio = 6;
+```
+
+```from ft232 usb to 6 pin female header manual
+
+ft232 pin and wire colour table converted to jtag signal names:
+
+```
+|-------|------|--------|----------|
+| Pin # | JTAG | FT232 | Colour |
+|-------|------|--------|----------|
+| 1 | VCC | VCC | Red |
+| 2 | GND | GND | Black |
+| 3 | TCK | TXD | White |
+| 4 | TDI | RXD | Green |
+| 5 | TDO | RTS | Yellow |
+| 6 | TMS | CTS | Blue |
+|-------|------|--------|----------|
+```
+Proposed FPGA External Pin to ft232r JTAG pin connections:
```
all pin #'s have headers pins on the fpga unless denoted as (no header)
______________________________________________________________________________
| | board | | | | |
-| | label | | |STLINKV2 JTAG | |
+| | label | | | ft232r JTAG | |
| pin # | # | FPGA IO PAD |GPIO # (n/p) | Pin # (Signal)|Wire Colour|
|_____________|_______|_____________|_____________|________________|___________|
|1 (no header)| 3.3v |NOT CONNECTED|NOT CONNECTED| NOT CONNECTED | NOT |
-|2 | 3.3v | IO VOLT REF | IO VOLT REF | 2 (MCU VDD) | Red |
+|2 | 3.3v | IO VOLT REF | IO VOLT REF | 3 (VCC) | Red |
|3 (no header)|-|(GND)|NOT CONNECTED|NOT CONNECTED| NOT CONNECTED | NOT |
-|4 |-|(GND)| NONE | GND | 4 (GND) | Black |
-|5 (J1_5-) | 0 | C11 | gn[0] | 5 (JTDI) | Green |
-|6 (J1_5+) | 0 | B11 | gp[0] | 7 (JTMS) | Blue |
-|7 (J1_7-) | 1 | A11 | gn[1] | 9 (JTCK) | White |
-|8 (J1_7+) | 1 | A10 | gp[1] | 13 (JTDO) | Yellow |
+|4 |-|(GND)| NONE | GND | 1 (GND) | Black |
+|5 (J1_5-) | 0 | C11 | gn[0] | 5 (TDI) | Green |
+|6 (J1_5+) | 0 | B11 | gp[0] | 2 (TMS) | Blue |
+|7 (J1_7-) | 1 | A11 | gn[1] | 4 (TCK) | White |
+|8 (J1_7+) | 1 | A10 | gp[1] | 6 (TDO) | Yellow |
|_____________|_______|_____________|_____________|________________|___________|
```
Complete diagram:
```
-Pins intentionally have no header or are not connected to the STLINKVT are marked
+Pins intentionally have no header or are not connected to the ft232 are marked
and therefore have no value are marked with 'NOT'
-(ST# JTAG) = (STLINKV2 pin # JTAG signal name)
-
+(ft232r# JTAG) = (ft232r pin # JTAG signal name)
J1
Wire Wire
Colour [GP{x}]|PCB label|[GN{x}] Colour
-(ST# JTAG) (Pin count +)(Pin count -) (ST# JTAG)
- ________________________V__________V_________________________
-| |
-|( 2 JVDD) red [VREF] 2 |3.3V| 1 NOT NOT NOT |
-|( 4 JGND) black [GND] 4 | -| | 3 NOT NOT NOT |
-|( 7 JTMS) blue [GP0] 6 | 0 | 5 [GN0] green (5 JTDI) |
-|(13 JTDO) yellow [GP1] 8 | 1 | 7 [GN1] white (9 JTCK) |
-|_____________________________________________________________|
+(ft232r# JTAG) (Pin count +)(Pin count -) (ft232r# JTAG)
+ ______________________V__________V_______________________
+| |
+|(3 VCC) red [VREF] 2 |3.3V| 1 NOT NOT NOT |
+|(1 GND) black [GND] 4 | -| | 3 NOT NOT NOT |
+|(2 TMS) Blue [GP0] 6 | 0 | 5 [GN0] Green (5 TDI) |
+|(6 TDO) Yellow [GP1] 8 | 1 | 7 [GN1] White (4 TCK) |
+|_________________________________________________________|
```
-## Images of wires on FPGA and on STLINKV2
+## Images of wires on ulx3s FPGA and on ft232r (lkcl to update images for Versa ECP5)
-[[!img HDL_workflow/jtag_wires_ulx3s_fpga.jpg size="200x" ]] [[!img HDL_workflow/jtag_wires_ulx3s_stlinkv2.jpg size="250x" ]]
+Image of JTAG jumper wire connections on ULX3S FPGA side:
-## Questions
+[[!img HDL_workflow/ulx3s_fpga_jtag_wires.jpg size="500x" ]]
-Luke do the labels of PCLK[C|T]0_[0|1] and GR_PCLK0_[0|1] have any significance? Should we be using the CLK labeled pins specifically for JTAG or specifically avoid using them for JTAG?
+Image of JTAG jumper wire connections on ft232r side:
-Additionally, does the note in the schematic about needing to swap EVEN and ODD pin numbers if using MALE VERTICAL header instead of FEMALE 90° ANGLED header apply to us?
+[[!img HDL_workflow/ft232r_jtag_wires.jpg size="500x" ]]
-# STLinkV2 connector
+Colour markings on ft232r side:
-[[!img 2020-11-03_14-08.png size="900x" ]]
-
-[[!img 2020-11-03_14-09.png size="900x" ]]
+[[!img HDL_workflow/ft232.png size="500x" ]]
# VERSA ECP5 Connections
Table of connections:
-| X3 pin # | FPGA IO PAD | STLinkv2 |Wire Colour|
-|-------------|-------------|----------------|-----------|
-|1 GND | GND | 4 (GND) | Black |
-|2 NC | NC | NC | NC |
-|3 +2V5 | 2.5V supply | 2 (MCU VDD) | Red |
-|4 IO29 | B19 | 5 (TDI) | Green |
-|5 IO30 | B12 | 7 (TMS) | Blue |
-|6 IO31 | B9 | 9 (TCK) | White |
-|7 IO32 | E6 | 13 (TDO) | Yellow |
+| X3 pin # | FPGA IO PAD | Function | FT232 | Wire Colour|
+|-------------|-------------|-----------|--------|------------|
+| 39 +3.3V | 3.3V supply | (VCC) | VREF | Red |
+| 1 GND | GND | (GND) | GND | Black |
+| 4 IO29 | B19 | (TDI) | RXD | Green |
+| 5 IO30 | B12 | (TMS) | CTS | Blue |
+| 6 IO31 | B9 | (TCK) | TXD | White |
+| 7 IO32 | E6 | (TDO) | RTS | Yellow |
[[!img 2020-11-03_13-22.png size="900x" ]]
[[!img 2020-11-03_13-25.png size="900x" ]]
[[!img versa_ecp5_x3_connector.jpg size="900x" ]]
+