Script - Separating bytes from ir4 during i2c reads

[letshin]

Edit: This Q&A was called something else but has been changed as I have made several tests and adjustments.

Hi, I have two i2c devices connected to an ESP 12F on GPIO2 and GPIO14 (SDA and SCL respectively)

The SHT4x works with the preset drivers, I am trying to change to script so I can read from both the SHT4x as well as the AGS10 (datasheet: http://www.aosong.com/userfiles/files/Datasheet%20AGS10.pdf: which appears to be reading 5 bytes from 0x00) using script.

I'm able to read the sensor using a minimal wire code from the Arduino IDE

#include "Wire.h"

uint8_t buffer[5];

void setup()
{
 delay(1000);
 Serial.begin(115200);

 Wire.begin(2,14);
 Wire.setClock(15000L);   
}

void loop()
{
 delay(3000);
 Wire.requestFrom(26, 5);
 for ( int i = 0; i < 5; i++)
 {
   buffer[i] = Wire.read();
 }
 Serial.println();

 //  CONVERT RAW DATA
 Serial.print("STAT:\t");
 Serial.println(buffer[0]);
 Serial.print("PPB:\t");
 Serial.println(buffer[1] * 65536UL + buffer[2] * 256 + buffer[3]);
 Serial.print("1:\t");
 Serial.println(buffer[1]);
 Serial.print("2:\t");
 Serial.println(buffer[2]);
 Serial.print("3:\t");
 Serial.println(buffer[3]);      
 Serial.print("CRC:\t");
 Serial.println(buffer[4]);
 Serial.println();
}

I'm trying to replicate this in script but am not sure how to 1)Separate out the bytes, and 2) Reduce the i2c speed. Can anyone advice please. Here is where I am so far on my current script. The first byte from 0x00 (the status bit) reads 16 which is the same as when I'm reading it from the code above, but I'm not sure how to extract the other values.

>D
found=0
val0=0
val1=0
val2=0
val3=0
val4=0
val5=0
val6=0
>B
; check device
found=ia(0x1a)
>S
if found>0 {
val0=ir1(0x00)
val2=ir4(0x00)

val4=val2-(256*256*256)

print %val0%
print %val1%
print %val2%
print %val3%
print %val4%
print %val5%
print %val6%
}

Output:

06:24:10.410 16.00
06:24:10.412 0.00
06:24:10.414 16777460.00
06:24:10.416 0.00
06:24:10.418 244.00
06:24:10.420 0.00
06:24:10.422 0.00

[barbudor]

If you want to drive the SHT4x from Scripting-Language, you need to disable the native driver using i2cdriver15 0. Don't mix both.

I'm not sure that scripting language can work with 2 different I2C peripheral at the same time.
Anyhow the address for the AGS10 is 0x34, not 0x44

[sfromis]

If they specifically mean bus speed (and not something like sample rate), 15 KHz would be surprisingly slow, typical I2C bus speeds are standard 100 KHz or fast 400 KHz. Looks like Tasmota is using 100 KHz, or maybe 400 KhZ on ESP32. However, the default expectation is that the bus would just be slowed down, which should be no problem unless the bus is shared with devices needing a higher speed.

[letshin]

Yes, I believe this would be bus speed. As there is a similar chip ags02ma that Adafruit uses (and warns on the clock speeds required) from what I assume to be the same family that is also limited to a low 30khz communication speed (datasheet : https://cdn-shop.adafruit.com/product-files/5593/datasheet+ags02ma.pdf). When I chose this particular chip I kinda didn't realise what that meant when going through the datasheet and am now paying the price. :/ There appears to be away to reduce the i2c rate but I need to spend some time understanding it first (esp8266/Arduino#2524)

[sfromis]

What I meant is that I see statements like this on the Internet:

If multiple devices with different i2c rates are interfaced on same bus, then the lowest should be the speed.

However, I do not know if this will always work, or if there may be caveats. Thus "I'd not be surprised" if it works anyway, but not going to make any assertions either way.

[letshin]

Sorted it for both sensors (without slowing down i2c speed, keeping stock values whatever they are) as :

>D
found=0
status=0
val0=0
val1=0
topic="test"
hum=0
temp=0

>B
; check device
found=ia(0x1a)

>S
;update TVOC every 3s
if upsecs%3==0 {
 val1=ir4(0x00)
 status=val1>>24
}
if found>0 {
 if val1>(status<<24) {
  val0=val1-(status<<24)
  ;print %val0%
 }
}

>T
temp=SHT4X#Temperature
hum=SHT4X#Humidity
=>Publish tele/%topic%/SENSOR {"Sensor":{"TVOC":%val0%,"Temperature":%temp%,"Humidity":%hum%}}