CC1101 receives perfectly but never transmits – tested with two different modules

[MP3550]

Hardware

ESP32

Firmware version

v2.4.6

Application version

v2.4.6

What happened? What did you expect to happen?

Setup: AZDelivery ESP32 Dev Kit C V4 (classic ESP32/WROOM-32), ESPSomfy-RTS v2.4.6, RTS protocol / 56-bit (confirmed via Logs tab, incoming frames show "56-S").

Pin mapping (SPI + shared or separate RX/TX both tested):

SCLK: GPIO 17, CSN: GPIO 16, MOSI: GPIO 5, MISO: GPIO 18
GDO0 (TX): GPIO 4 or GPIO 32 (tested both)
GDO2 (RX): GPIO 33, or shared with TX on same pin (tested both)

Symptom: Reception works perfectly — strong RSSI (-23 to -41 dBm), correct protocol/bit-length detected from the existing physical remote. Radio initializes correctly (no "Radio not Initialized"). However, the motor never responds to anything sent from ESPSomfy — not Pair Shade/Prog, not Up/Down/My via Virtual Remote, not the Repeater function (no outgoing retransmission observed either).

Serial log during a Prog attempt (no errors, command appears correctly processed):

Received:{"type":"shade","address":"583457","cmd":"Prog","shadeId":1,"shadeType":0,"command":"Prog"}
CMD:Prog ADDR:583457 RCODE:275 REPEAT:0

Already ruled out:

Two completely different CC1101 modules (generic "433M V2.0" clone, and E07-M1101D-SMA) — identical symptom on both
Shared and separate GDO0/GDO2 pins, avoiding strapping pins (0/2/12/15)
Tuning set to documented recommended values (RX BW ~96.94 kHz, Freq Deviation ~11.4-11.6 kHz), TX Power at max (12 dBm)
Antenna replaced/checked, firmly connected
Proper 5V USB power supply with short cable (ruled out brownout during TX current draw)
Fresh shade re-created (new remote address) in case of stale pairing state
Pairing timing (remote PROG jog immediately followed by ESPSomfy Prog click)

Any idea what else could cause TX to be silently "successful" in software but never actually radiate? Happy to provide more logs/photos of the wiring if useful.

Expected: After pairing (Prog) or sending Up/Down/My commands from ESPSomfy RTS, the Somfy RTS motor should react (jog to confirm pairing, or move for commands).

Actual: The motor never reacts to anything sent from ESPSomfy RTS. Receive works perfectly (existing physical remote is picked up in Logs, RSSI -23 to -41 dBm, correctly decoded as 56-bit RTS), but transmit produces no visible effect on the motor at all.

Already ruled out:

• Two different CC1101 modules tested (generic "433M V2.0" clone and E07-M1101D-SMA)
• Multiple TX/RX GPIO combinations (TX: GPIO4, GPIO32; RX: GPIO32, GPIO33)
• Radio tuning set to documented values (RX Bandwidth 96.94 kHz, Frequency Deviation 11.41 kHz, Base Frequency 433.420 MHz, TX Power 12 dBm max)
• Antenna replaced
• Powered via wall USB charger instead of PC USB port
• New Shade created with fresh remote address (rules out stale pairing/rolling code)
• Correct pairing timing (remote + device both in range, minimal delay between jog and Prog press)
• Serial log confirms firmware constructs and sends the command with no errors: CMD:Prog ADDR:583457 RCODE:275 REPEAT:0

How to reproduce it (step by step)

1. Flash ESP32 (AZDelivery ESP32 Dev Kit C V4) with ESPSomfy-RTS v2.4.6 (onboard build)
2. Wire CC1101 to ESP32: SCLK=GPIO17, CSN=GPIO16, MOSI=GPIO5, MISO=GPIO18, TX(GDO0)=GPIO4, RX(GDO2)=GPIO33
3. Configure Radio tab: RTS protocol, 56-bit, Base Frequency 433.420 MHz, RX Bandwidth 96.94 kHz, Frequency Deviation 11.41 kHz, TX Power 12 dBm (max)
4. Confirm RX works: existing physical Somfy remote is picked up in Logs tab, RSSI around -23 to -41 dBm, correctly decoded as 56-bit RTS
5. Add a new Shade (Awning type, new remote address to rule out stale pairing)
6. Try to pair: press Prog on existing remote until motor jogs (opens memory), then press "Prog" in ESPSomfy web UI within the time window
7. Expected: motor jogs again to confirm pairing
8. Actual: nothing happens — motor never reacts to any command sent from ESPSomfy (Prog, Up, Down, My via Virtual Remote)

Logs

Enabled receive on Pin #33 Timing: 0
CMD:Prog ADDR:583457 RCODE:275 REPEAT:0
Socket [0] Disconnected!

[patrickfrugier019-tech]

Hello,
I have the same behavior,
Hardware: ESP32-U 38 pins (UFL connector)
Module: CC1101 with SMA antenna (tested with 2 different modules)
Firmware: ESPSomfy RTS v2.4.6

GPIO config:
SCLK=18, CSN=5, MOSI=23, MISO=19, GDO0=13, GDO2=4

Issue: Cannot pair virtual shade with physical Somfy RTS motor.

• Reception works fine (Up/Down at -40dBm)
• Physical Prog button detected at -84dBm (normal for RTS)
• Motor jogs on physical Prog press
• No second jog when sending Prog from ESPSomfy
• Pairing sequence timing is correct (<1 second between jogs)
• Tested with 2 CC1101 modules, same result
• Tested GPIO 2, 4, 12 for GDO2, no change

Question: Is there a known issue with ESP32-U variant or specific GPIO conflicts with this hardware?

[jaarsa]

It looks like ESPSomfy‑RTS simply doesn’t support the ESP32 DevKitC V4 + CC1101 combination at the moment. RX works perfectly, but TX never produces a valid RTS frame, even though the firmware believes it is transmitting. Two CC1101 modules tested, multiple pins tested, full tuning verified — same result.

This points to a firmware‑side issue (SPI init or TX FIFO write) specific to the DevKitC V4. Other ESP32 boards work fine.

I would stick to the Hardware WiKi, if I were you.
https://github.com/rstrouse/ESPSomfy-RTS/wiki/Simple-ESPSomfy-RTS-device
OLIMEX ESP32‑POE is a good option, and both ESP8266 and ESP32‑C3 boards are confirmed working with CC1101.