https://github.com/lupyuen/pinephone-lora
Experimenting with LoRa Backplate for PinePhone
https://github.com/lupyuen/pinephone-lora
arm64 i2c lora manjaro pinephone spi sx1262
Last synced: 4 months ago
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Experimenting with LoRa Backplate for PinePhone
- Host: GitHub
- URL: https://github.com/lupyuen/pinephone-lora
- Owner: lupyuen
- License: apache-2.0
- Created: 2021-10-31T23:15:12.000Z (over 4 years ago)
- Default Branch: main
- Last Pushed: 2021-12-07T09:24:21.000Z (over 4 years ago)
- Last Synced: 2025-09-03T02:34:58.303Z (9 months ago)
- Topics: arm64, i2c, lora, manjaro, pinephone, spi, sx1262
- Homepage:
- Size: 30.3 KB
- Stars: 15
- Watchers: 2
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Funding: .github/FUNDING.yml
- License: LICENSE
Awesome Lists containing this project
README
# Experimenting with LoRa Backplate for PinePhone
Follow the updates on Twitter: https://twitter.com/MisterTechBlog/status/1454200499247349760
LoRa Backplate for PinePhone consists of...
- Semtech SX1262 LoRa Transceiver (SPI) and antenna
https://www.semtech.com/products/wireless-rf/lora-core/sx1262
- I2C Connector that matches the I2C Port (Pogo Pins) on PinePhone
https://wiki.pine64.org/index.php/PinePhone#Pogo_pins
- I2C-To-SPI Bridge (ATtiny84) that connects the I2C Connector to the LoRa Transceiver (SPI)
https://github.com/zschroeder6212/tiny-i2c-spi
Schematic: https://wiki.pine64.org/wiki/Pinedio#Pinephone_backplate
Let's probe the LoRa Backplate with a Bus Pirate, to transmit some SX1262 commands and read the responses: http://dangerousprototypes.com/docs/I2C
UPDATE: See these excellent articles by JF...
- ["First look at the LoRa backplate for the Pinephone"](https://codingfield.com/blog/2021-11/first-look-at-lora-pinephone-backplate/)
- ["Flashing the LoRa backplate for the PinePhone"](https://codingfield.com/blog/2021-11/flash-the-lora-pinephone-backplate/)
- ["A driver for the LoRa backplate for the PinePhone"](https://codingfield.com/blog/2021-11/a-driver-for-the-pinephone-lora-backplate/)
# I2C-To-SPI Bridge
Arduino Source Code: https://github.com/zschroeder6212/tiny-i2c-spi/blob/master/src/main.c
The bridge runs at I2C Address 0x28:
```c
#include "USI_TWI_Slave.h"
#define I2C_ADDR 0x28
int main (void)
{
/* init I2C */
usiTwiSlaveInit(I2C_ADDR);
/* set received/requested callbacks */
usi_onReceiverPtr = I2C_received;
usi_onRequestPtr = I2C_requested;
```
The bridge transmits data to SPI when the first byte received is 0x01:
```c
#define CMD_TRANSMIT 1
#define CMD_CONFIGURE 2
void I2C_received(uint8_t bytes_recieved)
{
uint8_t command = usiTwiReceiveByte();
switch(command)
{
case CMD_TRANSMIT:
{
CS_PORT &= ~(1<= BUFFER_SIZE)
{
transmit_index = 0;
}
}
```
`usi` functions are defined here: https://github.com/zschroeder6212/tiny-i2c-spi/blob/master/src/USI_TWI_Slave.c
# Probe LoRa Backplate with Bus Pirate
Based on:
- http://dangerousprototypes.com/docs/I2C
- https://lupyuen.github.io/articles/i2c#appendix-test-bme280-with-bus-pirate
Connect Bus Pirate to LoRa Backplate:
| Bus Pirate Pin | Backplate Pin
|:---:|:---:
| __`MOSI`__ | `SDA`
| __`CLK`__ | `SCL`
| __`5V`__ | `USB-5V`
| __`GND`__ | `GND`
Enter I2C mode, power on:
```text
m
I2C > HW > 400
W
```
Scan I2C bus:
```text
(1)
```
I2C scan results:
```text
Searching I2C address space. Found devices at:
0x00 (0x00 W) 0x01 (0x00
```
or
```text
Searching I2C address space. Found devices at:
0x40(0x20 W) 0x41(0x20
```
__Problem: Bus Pirate hangs while scanning. And I2C Address of LoRa Backplate should be 0x28, not 0x00. Why?__
Read I2C Address 0x28:
```text
[0x51 r]
```
(Because 0x51 = 0x28 * 2 + 1)
Result:
```text
I2C START BIT
WRITE: 0x51 ACK
READ: 0x00
NACK
```
__Problem: Bus Pirate hangs while reading I2C Address 0x28 from LoRa Backplate. Why?__
Read I2C Address 0x20:
```text
[0x41 r]
```
(Because 0x41 = 0x20 * 2 + 1)
Same problem as above.
Read I2C Address 0x00:
```text
[0x01 r]
```
(Because 0x01 = 0x00 * 2 + 1)
Same problem as above.
Same thing happens when we probe the Breakout Board for LoRa Backplate...
TODO: Write and Read I2C Address 0x28 Register 0x01:
```text
[0x50 0x01 0x00] [0x51 r]
```
TODO: Write and Read I2C Address 0x00 Register 0x01?
```text
[0x00 0x01 0x00] [0x01 r]
```
# Test LoRa Backplate on PinePhone
On PinePhone with Manjaro Phosh, scanning I2C Bus 3 with `i2cdetect`:
```bash
[manjaro@manjaro-arm ~]$ sudo pacman -Syu i2c-tools
[manjaro@manjaro-arm ~]$ i2cdetect -l
i2c-0 unknown DesignWare HDMI N/A
i2c-1 unknown mv64xxx_i2c adapter N/A
i2c-2 unknown mv64xxx_i2c adapter N/A
i2c-3 unknown mv64xxx_i2c adapter N/A
i2c-4 unknown i2c-csi N/A
i2c-5 unknown i2c-2-mux (chan_id 0) N/A
[manjaro@manjaro-arm ~]$ sudo i2cdetect 3
WARNING! This program can confuse your I2C bus, cause data loss and worse!
I will probe file /dev/i2c-3.
I will probe address range 0x08-0x77.
Continue? [Y/n]
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --
```
__Problem: `i2cdetect` fails to detect the I2C Address (0x28) of the LoRa Backplate. Why?__
Has the LoRa Backplate been flashed with the right firmware?
I2C-To-SPI Bridge on ATtiny84: https://github.com/zschroeder6212/tiny-i2c-spi
LoRa Backplate (I2C Address 0x28) doesn't appear when we scan I2C Buses 0 to 5:
```bash
[manjaro@manjaro-arm ~]$ sudo i2cdetect 0
WARNING! This program can confuse your I2C bus, cause data loss and worse!
I will probe file /dev/i2c-0.
I will probe address range 0x08-0x77.
Continue? [Y/n]
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: 30 -- 32 -- -- 35 -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: 50 51 52 53 54 55 56 57 58 59 5a 5b 5c 5d 5e 5f
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --
[manjaro@manjaro-arm ~]$ sudo i2cdetect 1
WARNING! This program can confuse your I2C bus, cause data loss and worse!
I will probe file /dev/i2c-1.
I will probe address range 0x08-0x77.
Continue? [Y/n]
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- UU -- -- -- UU -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- UU -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --
[manjaro@manjaro-arm ~]$ sudo i2cdetect 2
WARNING! This program can confuse your I2C bus, cause data loss and worse!
I will probe file /dev/i2c-2.
I will probe address range 0x08-0x77.
Continue? [Y/n]
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- UU --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- UU -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- UU -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --
[manjaro@manjaro-arm ~]$ sudo i2cdetect 3
WARNING! This program can confuse your I2C bus, cause data loss and worse!
I will probe file /dev/i2c-3.
I will probe address range 0x08-0x77.
Continue? [Y/n]
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --
[manjaro@manjaro-arm ~]$ sudo i2cdetect 4
WARNING! This program can confuse your I2C bus, cause data loss and worse!
I will probe file /dev/i2c-4.
I will probe address range 0x08-0x77.
Continue? [Y/n]
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- UU -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- UU -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --
[manjaro@manjaro-arm ~]$ sudo i2cdetect 5
WARNING! This program can confuse your I2C bus, cause data loss and worse!
I will probe file /dev/i2c-5.
I will probe address range 0x08-0x77.
Continue? [Y/n]
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- UU --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- UU -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- UU -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --
```
(Nope it can't be I2C Bus 2 because we're expecting an entire bus dedicated for the I2C Pogo Pins)
Compare this with other PinePhone I2C devices:
https://github.com/jnavarro7/pineeye_for_pinephone
https://dev.to/pcvonz/i-c-on-the-pinephone-5090
UPDATE: See these excellent articles by JF...
- ["First look at the LoRa backplate for the Pinephone"](https://codingfield.com/blog/2021-11/first-look-at-lora-pinephone-backplate/)
- ["Flashing the LoRa backplate for the PinePhone"](https://codingfield.com/blog/2021-11/flash-the-lora-pinephone-backplate/)
- ["A driver for the LoRa backplate for the PinePhone"](https://codingfield.com/blog/2021-11/a-driver-for-the-pinephone-lora-backplate/)
