TangNano9K with RPi4 and openFPGALoader

[h3ifri]

Hi!

I’m trying to get the TangNano9K working with a Raspberry Pi 4 using openFPGALoader, but so far I haven’t had any success.

Sometimes the board is recognized, but on the second attempt I get errors and flashing becomes impossible:

h3ifri@picnc:~ $ sudo openFPGALoader --freq 500000 --detect --board tangnano9k
empty
Jtag frequency : requested 500.00KHz -> real 500.00KHz
index 0:
        idcode 0x100481b
        manufacturer Gowin
        family GW1N
        model  GW1N(R)-9C
        irlength 8

h3ifri@picnc:~ $ sudo openFPGALoader --freq 500000 --detect --board tangnano9k
empty
Can't read iProduct field from FTDI: considered as empty string
Can't read iSerialNumber field from FTDI: considered as empty string
FTDI reset error with code -1 (FTDI reset failed)
unable to config pins : -1 unable to configure bitbang mode. Perhaps not a BM/2232C type chip?
JTAG init failed with: low level FTDI init failed

h3ifri@picnc:~ $ sudo openFPGALoader --freq 500000 --detect --board tangnano9k
empty
Jtag frequency : requested 500.00KHz -> real 500.00KHz
index 0:
        idcode 0x100481b
        manufacturer Gowin
        family GW1N
        model  GW1N(R)-9C
        irlength 8

h3ifri@picnc:~ $ sudo openFPGALoader --freq 500000 --detect --board tangnano9k
empty
unable to open ftdi device: -6 (ftdi_usb_reset failed)
JTAG init failed with: unable to open ftdi device

h3ifri@picnc:~ $ sudo openFPGALoader --freq 500000 --detect --board tangnano9k
empty
unable to open ftdi device: -6 (ftdi_usb_reset failed)
JTAG init failed with: unable to open ftdi device  

I’ve tried both:

• rpi-4-debian-bookworm-6.12.11-arm64-ext4-2025-01-27-0404
• image_2025-11-12-raspios-lcnc-2.9.7-rc3-trixie-arm64

Any suggestions on how to reliably flash the TangNano9K from an RPi4?

Thanks in advance!

[multigcs]

This is a well-known problem; unfortunately, this combination does not work with Raspberry.
Linux works on a normal PC, Windows works, openFPGA with ICE40 works, but Tang+RPI does not :(

[h3ifri]

The TangNano9K uses a BL702 as its JTAG interface. Do you know if the TangPrimer25K, which uses a BL616, will work with the RPi4? It even exposes the JTAG pins for use with an external probe.

[multigcs]

If I don't forget, I can try it tonight. I have the 25k at home.

[h3ifri]

I just found spi_prog and spiflash.sh - can these be used to flash the TangNano9K via SPI directly from the RPi?

[h3ifri]

I already flashed the board once using Windows, but I’m looking for a more convenient way to update it when everything is hooked up to the RPi, so doing updates via SPI would be ideal. Which branch should I use, main or dev?

[h3ifri]

I get a size mismatch, on main branch:

./flashrom/builddir/flashrom -p linux_spi:dev=/dev/spidev0.0,spispeed=7000 -w ./riocore/Output/TangNano9K/Gateware/rio.fs
flashrom v1.7.0-devel (git:v1.6.0-55-g214a0bd9) on Linux 6.12.34+rpt-rpi-v8-rt (aarch64)
flashrom is free software, get the source code at https://flashrom.org

===
SFDP has autodetected a flash chip.
All standard operations (read, verify, erase and write) should work.
Additionally, flashrom supports RPMC commands via SFDP autodetection.
We may add support for more features via SFDP in future.
If you are interested, join us on the mailing list https://flashrom.org/contact.html#mailing-list-1
===
Found Unknown flash chip "SFDP-capable chip" (4096 kB, SPI) on linux_spi.
Error: Image size (2069320 B) doesn't match the expected size (4194304 B)!

PININ_SPI_PROG0_PROG is pulled high with: pinctrl set 25 op dh

[multigcs]

not sure if it works with .fs file, but for the iceshield i use dd to create the right size:
you can try something like this:

dd if=/dev/zero of=/tmp/_flash.bin  bs=4096k count=1
dd if=./riocore/Output/TangNano9K/Gateware/rio.fs conv=notrunc of=/tmp/_flash.bin 2> /dev/null
flashrom -p linux_spi:dev=/dev/spidev0.0,spispeed=7000 -w /tmp/_flash.bin

[multigcs]

https://gist.github.com/ciniml/e02f4cc9b00f30d950cd2a787a1ea8d3

[h3ifri]

Hm, I don't know whats going on :). I can write the rom, read the rom, the two files are identical. But the FPGA still runs the old program. Do I need a reset? I power cycle the board to do it.

h3ifri@picnc:~/LinuxCNC $ pinctrl set 25 op dh

h3ifri@picnc:~/LinuxCNC $ python fs2bin.py ./riocore/Output/TangNano9K/Gateware/rio.fs rio_fs2bin.bin
Bytes written from input: 258574

h3ifri@picnc:~/LinuxCNC $ ./flashrom/builddir/flashrom -p linux_spi:dev=/dev/spidev0.0,spispeed=2000 -w rio_fs2bin.bin
flashrom v1.7.0-devel (git:v1.6.0-55-g214a0bd9) on Linux 6.12.34+rpt-rpi-v8-rt (aarch64)
flashrom is free software, get the source code at https://flashrom.org
===
SFDP has autodetected a flash chip.
All standard operations (read, verify, erase and write) should work.
Additionally, flashrom supports RPMC commands via SFDP autodetection.
We may add support for more features via SFDP in future.
If you are interested, join us on the mailing list https://flashrom.org/contact.html#mailing-list-1
===
Found Unknown flash chip "SFDP-capable chip" (4096 kB, SPI) on linux_spi.
Reading old flash chip contents... done.
Updating flash chip contents... Erase/write done from 0 to 3fffff
double free or corruption (!prev)
Aborted

h3ifri@picnc:~/LinuxCNC $ ./flashrom/builddir/flashrom -p linux_spi:dev=/dev/spidev0.0,spispeed=2000 -r rio_read.bin
flashrom v1.7.0-devel (git:v1.6.0-55-g214a0bd9) on Linux 6.12.34+rpt-rpi-v8-rt (aarch64)
flashrom is free software, get the source code at https://flashrom.org
===
SFDP has autodetected a flash chip.
All standard operations (read, verify, erase and write) should work.
Additionally, flashrom supports RPMC commands via SFDP autodetection.
We may add support for more features via SFDP in future.
If you are interested, join us on the mailing list https://flashrom.org/contact.html#mailing-list-1
===
Found Unknown flash chip "SFDP-capable chip" (4096 kB, SPI) on linux_spi.
Reading flash... done.

h3ifri@picnc:~/LinuxCNC $ cmp rio_read.bin rio_fs2bin.bin
h3ifri@picnc:~/LinuxCNC $ pinctrl set 25 op dl

My modified fs2bin.py:

#!/usr/bin/env python3

import sys

FLASH_SIZE = 4194304  # 4 MB

if len(sys.argv) != 3:
    print(f"Usage: {sys.argv[0]} <input_file> <output_file>")
    sys.exit(1)

input_path = sys.argv[1]
output_path = sys.argv[2]

buffer = bytearray(b'\xFF' * FLASH_SIZE)
buffer_index = 0 

with open(input_path, 'r') as input_file:
    for line in iter(input_file.readline, ''):  # type: str
        line = line.strip()
        if line.startswith('//') or len(line) == 0:
            continue
        for byte_index in range(0, len(line), 8):
            if buffer_index >= FLASH_SIZE:
                print(f"Error: Input larger flash size")
                break
            value = 0
            for bit_index in range(8):
                if byte_index + bit_index >= len(line):
                    bit = '0'
                else:
                    bit = line[byte_index + bit_index]
                value = (value << 1) | (1 if bit == '1' else 0)
            buffer[buffer_index] = value
            buffer_index += 1

with open(output_path, 'wb') as output_file:
    output_file.write(buffer)

print(f"Bytes written from input: {buffer_index}")

[multigcs]

tangprimer25k works on rpi4

cnc@raspberrypi:~$ /home/cnc/riocore/toolchains/oss-cad-suite/bin/openFPGALoader -b tangprimer25k RPI/TangPrimer25K/Gatewa
re/board0/impl/pnr/project.fs -f 
empty
write to flash
Jtag frequency : requested 6.00MHz   -> real 6.00MHz  
Parse file Parse RPI/TangPrimer25K/Gateware/board0/impl/pnr/project.fs: 
Done
DONE
Jtag frequency : requested 2.50MHz   -> real 2.50MHz  
after program flash: displayReadReg 70026020
	   [ 5] Memory Erase
	   [13] Done Final
	   [14] Security Final
	   [17] sspi_mode
	[24:23] CPU Bus Width: no BWD pattern is detected
	[26:25] Retry time sync pattern detect: no retry
	   [28] OTP Reading Done
	   [29] Init Done
	   [30] Wakeup Done
Erase SRAM DONE
Erase SRAM DONE
Jtag frequency : requested 10.00MHz  -> real 10.00MHz 
Detail: 
Jedec ID          : 0b
memory type       : 40
memory capacity   : 17
Detail: 
Jedec ID          : 0b
memory type       : 40
memory capacity   : 17
RDSR : 0x00
WIP  : 0
WEL  : 0
BP   : 0
TB   : 0
SRWD : 0
flash chip unknown: use basic protection detection
start addr: 00000000, end_addr: 000c0000
Erasing: [==================================================] 100.00%
Done
Writing: [==================================================] 100.00%
Done

[h3ifri]

Just found out that the TangNano9K works finde on my RPi5... I will try with this setup to get my CNC working.

[h3ifri]

After I start LinuxCNC and press F1, I get this:

h3ifri@picnc:~/LinuxCNC/riocore/Output/GP10050/LinuxCNC $ bash start.sh
++ dirname start.sh
+ DIRNAME=.
+ linuxcnc ./rio.ini
LINUXCNC - 2.9.7
Machine configuration directory is '/home/h3ifri/LinuxCNC/riocore/Output/GP10050/LinuxCNC/.'
Machine configuration file is 'rio.ini'
Starting LinuxCNC...
linuxcnc TPMOD=tpmod HOMEMOD=homemod EMCMOT=motmod
Note: Using POSIX realtime
twopass:invoked with <> options
twopass:found ./rio.hal
twopass:found ./pregui_call_list.hal
twopass:pass0: loadusr -W hal_manualtoolchange
# compiling and loading rio component...done
Info: Initialize SPI5 connection
note: MAXV     max: 45.000 units/sec 2700.000 units/min
note: LJOG     max: 45.000 units/sec 2700.000 units/min
note: LJOG default: 40.000 units/sec 2400.000 units/min
note: jog_order='XYZ'
note: jog_invert=set()
link (updating variable file): No such file or directory
wronng data (1/3): 97 116 102 23 70 22 64 120 133 95 240 0 0 0 0 0 0 0 0 0 0 0 10 0 0
recovered..
wronng data (1/3): 97 116 96 194 232 194 201 230 86 175 254 0 0 0 0 0 0 0 0 0 0 0 1 64 0
wronng data (2/3): 97 115 11 163 11 38 148 162 191 248 0 0 0 0 0 0 0 0 0 0 0 5 0 0 0
wronng data (3/3): 97 116 96 194 232 194 201 163 252 175 254 0 0 0 0 0 0 0 0 0 0 0 1 64 0
wronng data (4/3): 97 116 102 23 70 22 65 118 133 143 240 0 0 0 0 0 0 0 wronng data (1/3): 97 116 102 23 70 22 77 243 181 159 240 0 0 0 0 0 0 0 0 0 0 0 10 0 0
wronng data (2/3): 97 108 46 140 44 154 212 139 63 224 0 0 0 0 0 0 0 0 0 0 0 20 0 0 0
recovered..
wronng data (1/3): 97 116 96 194 232 194 200 181 14 185 254 0 0 0 0 0 0 0 0 0 0 0 1 64 0
wronng data (2/3): 97 116 102 23 70 22 76 95 5 207 240 0 0 0 0 0 0 0 0 0 0 0 10 0 0
recovered..
wronng data (1/3): 97 116 102 23 70 22 66 2 213 239 240 0 0 0 0 0 0 0 0 0 0 0 10 0 0
recovered..
wronng data (1/3): 102 23 70 22 68 211 182 15 240 0 0 0 0 0 0 0 0 0 0 0 10 0 0 0 0
recovered..
wronng data (1/3): 97 116 102 23 70 22 74 39 150 31 240 0 0 0 0 0 0 0 0 0 0 0 10 0 0
wronng data (2/3): 97 115 10 194 232 194 200 221 198 195 254 0 0 0 0 0 0 0 0 0 0 0 1 64 0
recovered..
wronng data (1/3): 102 23 70 22 70 241 230 63 240 0 0 0 0 0 0 0 0 0 0 0 10 0 0 0 0
recovered..
wronng data (1/3): 97 116 102 23 70 22 73 146 230 95 240 0 0 0 0 0 0 0 0 0 0 0 10 0 0
recovered..
wronng data (1/3): 102 23 70 22 77 118 150 111 240 0 0 0 0 0 0 0 0 0 0 0 10 0 0 0 0
wronng data (2/3): 97 108 46 140 44 146 186 108 223 224 0 0 0 0 0 0 0 0 0 0 0 20 0 0 0
recovered..
wronng data (1/3): 97 108 46 140 44 147 66 13 31 224 0 0 0 0 0 0 0 0 0 0 0 20 0 0 0
recovered..
wronng data (1/3): 97 108 46 140 44 135 145 45 95 224 0 0 0 0 0 0 0 0 0 0 0 20 0 0 0
recovered..
wronng data (1/3): 97 108 46 140 44 142 56 173 127 224 0 0 0 0 0 0 0 0 0 0 0 20 0 0 0
wronng data (2/3): 102 23 70 22 72 114 230 207 240 0 0 0 0 0 0 0 0 0 0 0 10 0 0 0 0
wronng data (3/3): 97 108 46 140 44 145 83 13 159 224 0 0 0 0 0 0 0 0 0 0 0 20 0 0 0
wronng data (4/3): 97 116 102 23 70 22 75 80 38 223 240 0 0 0 0 0 0 0 wronng data (1/3): 97 116 102 23 70 22 76 186 182 239 240 0 0 0 0 0 0 0 0 0 0 0 10 0 0
recovered..
wronng data (1/3): 97 108 46 140 44 139 124 141 255 224 0 0 0 0 0 0 0 0 0 0 0 20 0 0 0
wronng data (2/3): 97 116 96 194 232 194 201 210 156 225 254 0 0 0 0 0 0 0 0 0 0 0 1 64 0
wronng data (3/3): 97 133 97 118 23 70 22 72 203 135 15 240 0 0 0 0 0 0 0 0 0 0 0 10 0
recovered..
wronng data (1/3): 97 108 46 140 44 148 49 78 63 224 0 0 0 0 0 0 0 wronng data (1/3): 97 116 96 194 232 194 200 115 144 229 254 0 0 0 0 0 0 0 0 0 0 0 1 64 0
wronng data (2/3): 97 108 46 194 232 194 200 140 98 231 254 0 0 0 0 0 0 0 0 0 0 0 1 64 0
recovered..
wronng data (1/3): 102 23 70 22 67 102 199 79 240 0 0 0 0 0 0 0 0 0 0 0 10 0 0 0 0
wronng data (2/3): 97 108 46 140 44 138 26 206 159 224 0 0 0 0 0 0 0 0 0 0 0 20 0 0 0
recovered..
wronng data (1/3): 97 116 97 116 97 100 47 19 118 255 0 0 0 0 0 0 0 wronng data (3/3): 97 116 97 116 97 100 178 230 118 255 0 0 0 0 0 0 0 0 0 0 0 0 160 0 0
wronng data (4/3): 97 108 46 140 44 137 137 238 255 224 0 0 0 0 0 0 0 0 0 0 0 20 0 0 0
too many errors..
wronng data (5/3): 97 116 96 194 232 194 201 101 114 239 254 0 0 0 0 0 0 0 0 0 0 0 1 64 0
too many errors..
wronng data (6/3): 97 108 46 140 44 135 36 79 31 224 0 0 0 0 0 0 0 0 0 0 0 20 0 0 0
too many errors..
wronng data (7/3): 97 116 96 194 232 194 201 73 24 241 254 0 0 0 0 0 wronng data (1/3): 97 116 102 23 70 22 73 174 119 223 240 0 0 0 0 0 0 0 0 0 0 0 10 0 0
recovered..
wronng data (1/3): 97 115 11 163 11 33 68 107 255 248 0 0 0 0 0 0 0 0 0 0 0 5 0 0 0
wronng data (2/3): 97 116 102 23 70 22 69 95 119 255 240 0 0 0 0 0 0 0 0 0 0 0 10 0 0
recovered..
wronng data (1/3): 102 23 70 22 70 35 40 31 240 0 0 0 0 0 0 0 0 0 0 0 10 0 0 0 0
recovered..
wronng data (1/3): 97 133 209 134 23 70 22 68 176 120 47 240 0 0 0 0 0 0 0 0 0 0 0 10 0
recovered..
wronng data (1/3): 97 116 102 23 70 22 73 36 56 63 240 0 0 0 0 0 0 0 0 0 0 0 10 0 0
recovered..
wronng data (1/3): 97 116 102 23 70 22 65 129 104 79 240 0 0 0 0 0 0 0 0 0 0 0 10 0 0
recovered..
wronng data (1/3): 97 116 97 102 23 70 22 71 190 152 79 240 0 0 0 0 0 0 0 0 0 0 0 10 0
wronng data (2/3): 97 133 209 134 23 70 22 65 85 56 95 240 0 0 0 0 0 0 0 0 0 0 0 10 0
recovered..
wronng data (1/3): 97 116 96 194 232 194 201 47 31 13 254 0 0 0 0 0 wronng data (1/3): 102 23 70 22 71 246 24 127 240 0 0 0 0 0 0 0 0 0 0 0 10 0 0 0 0
recovered..
wronng data (1/3): 97 116 102 23 70 22 79 131 72 143 240 0 0 0 0 0 0 0 0 0 0 0 10 0 0
wronng data (2/3): 97 116 102 23 70 22 69 233 232 143 240 0 0 0 0 0 0 0 0 0 0 0 10 0 0
recovered..
wronng data (1/3): 97 116 96 194 232 194 200 7 183 19 254 0 0 0 0 0 0 0 0 0 0 0 1 64 0

And with test-gui:

loading config: /usr/src/riocore/tn9k_triplebeast.json
loading board: /usr/src/riocore/riocore/boards/TangNano9K/board.json
starting testgui.. (/usr/src/riocore/bin/rio-test)
QStandardPaths: XDG_RUNTIME_DIR not set, defaulting to '/tmp/runtime-root'
loading board setup: TangNano9K
connection via: SPI
SPI: using bus:0 and device:0
ERROR(0): reveived data have wrong header: 0x61 0x6B 0xA 0xC2
ERROR(0): reveived data have wrong header: 0x61 0x74 0x66 0x16
ERROR(0): reveived data have wrong header: 0x61 0x6B 0xA 0xC2
ERROR(0): reveived data have wrong header: 0x61 0x6B 0xA 0xC2
ERROR(0): reveived data have wrong header: 0x61 0x6B 0xA 0xC2
ERROR(0): reveived data have wrong header: 0x61 0x6B 0xA 0xC2
ERROR(0): reveived data have wrong header: 0x61 0x6B 0xA 0xC2
ERROR(0): reveived data have wrong header: 0x61 0x6B 0xA 0xC2
ERROR(0): reveived data have wrong header: 0x61 0x6B 0xA 0xC2
ERROR(0): reveived data have wrong header: 0x61 0x6B 0xA 0xC2
ERROR(0): reveived data have wrong header: 0x61 0x6B 0xB 0xA3
ERROR(1): reveived data have wrong header: 0x61 0x6B 0xA 0xC2
ERROR(0): reveived data have wrong header: 0x61 0x6B 0xA 0xC2
ERROR(1): reveived data have wrong header: 0x61 0x6B 0xA 0xC2
ERROR(0): reveived data have wrong header: 0x61 0x85 0x66 0x16
ERROR(0): reveived data have wrong header: 0x61 0x6B 0xA 0xC2
ERROR(0): reveived data have wrong header: 0x61 0x6B 0xA 0xC2

Could you please provide some hints?

Thanks,
Heiko

[multigcs]

if you get an answer, then it sends the right header to the FPGA, so, there is something wrong in the answer frame.

ERROR(1): reveived data have wrong header: 0x61 0x6B 0xA 0xC2
ERROR(0): reveived data have wrong header: 0x61 0x85 0x66 0x16

the header in the response is changing, so there is a problem with the SPI connection,

• too long wires !?!? (most problem, if all other is set to default)
• SPI speed too high (set to default)
• FPGA speed too high (timing problem / set to default)

[h3ifri]

My jumper wires are 15cm, I did not change SPI oder FPGA speed from defaults.

"boardcfg": "TangNano9K" ----> "clock": {
"speed": "27000000",
"pin": "52"
},

interface.c_rpi5 ----> static uint32_t speed = 1500000;
interface.py ----> self.spi.max_speed_hz = 2000000

[h3ifri]

Sorry, I assumed that ground via USB cable is enough, but is was not...