adding step by step documentation on how to update the refresh rate f…

…or the MLX90632 standard mode
melexis · Oct 30, 2024 · 3f63fce · 3f63fce
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diff --git a/doc/mlx90632/media/datasheet_eemeas1_2_refresh_rate_table.png b/doc/mlx90632/media/datasheet_eemeas1_2_refresh_rate_table.png
diff --git a/doc/mlx90632/media/datasheet_unlock_eeprom_customer.png b/doc/mlx90632/media/datasheet_unlock_eeprom_customer.png
diff --git a/doc/mlx90632/refresh_rate_update.md b/doc/mlx90632/refresh_rate_update.md
@@ -0,0 +1,102 @@
+Below is a listing from the I2C Stick console where I took one MLX90632, starting with the default refresh rate, then I erase both 24E1 and 24E2 addresses, then I write the new content.
+
+The `<-` sign indicates that what I entered in the console, while the `->` sign indicates the answer from the I2C Stick (and thus indirectly what MLX90632 answers on the I2C bus).
+
+First let's start with how the I2C Stick command for I2C looks like: (please don't be bothered too much with the syntax, this is background, and is I2C Stick specific, not related to MLX90632)
+```
+2024/10/29 09:36:32.771 <- sos:i2c
+2024/10/29 09:36:32.773 -> I2C command format:
+2024/10/29 09:36:32.775 -> 1] WRITE         : 'i2c:<sa>:W<byte#0><byte#1>...' bytes in hex format
+2024/10/29 09:36:32.776 -> 2] READ          : 'i2c:<sa>:R<amount of bytes to read>' amount in decimal format
+2024/10/29 09:36:32.777 -> 3] ADDRESSED READ: 'i2c:<sa>:W<byte#0><byte#1>R<amount of bytes to read>...' bytes in hex format, amount in decimal
+2024/10/29 09:36:32.778 -> <sa> Slave Address(7-bit) in hex format
+```
+==> So there are three I2C flavors of the I2C command, we will use only the first and the last one!
+
+
+The next line will read 6 bytes from address 24E0 from slave 3A.
+```
+2024/10/29 09:14:45.118 <- i2c:3A:W24E0R06
+2024/10/29 09:14:45.120 -> i2c:3A:24E0:R:070B820D821D:OK
+```
+So in the line above you can see that the first word at address 24E0 is 070B, then at 24E1 820D, and finally at 24E2 it reads 821D
+
+Now we are entering the HALT mode, this is a mode where the MLX90632 goes to sleep mode immediately, the other modes would wait until the current conversion is finished. So we first read 2 bytes from 0x3001 ==> content is 0006.
+
+```
+2024/10/29 09:20:56.119 <- i2c:3A:W3001R02
+2024/10/29 09:20:56.121 -> i2c:3A:3001:R:0006:OK
+2024/10/29 09:21:27.133 <- i2c:3A:W30010000
+2024/10/29 09:21:27.135 -> i2c:3A:30010000:OK
+2024/10/29 09:21:36.502 <- i2c:3A:W3001R02
+2024/10/29 09:21:36.504 -> i2c:3A:3001:R:0000:OK
+```
+As mode is bit 1 & 2, the mode was 3, and it turns out all other bits were at zero, so mode HALT(0) corresponds to writing zero to 3001 (REG_CONTROL), the last command reads again, and it is confirmed 3001 is now 0000.
+
+The next command below, is `unlock`.  
+See datasheet: (https://melexis.com/mlx90632)
+image.png
+![datasheet_unlock_eeprom_customer.png](media/datasheet_unlock_eeprom_customer.png)
+It is equivalent of writing 554C to address 3005.
+Note: you cannot read this to verify, and it will last only one write operation.
+
+```
+2024/10/29 09:23:29.773 <- i2c:3A:W3005554C     // unlock
+2024/10/29 09:23:29.775 -> i2c:3A:3005554C:OK   // OK here means that there was an ACK seen by the master
+```
+First write zeros into 24E1
+```
+2024/10/29 09:23:41.697 <- i2c:3A:W24E10000       // erase 24E1
+2024/10/29 09:23:41.700 -> i2c:3A:24E10000:OK
+2024/10/29 09:23:44.886 <- i2c:3A:W24E0R06
+2024/10/29 09:23:44.889 -> i2c:3A:24E0:R:070B0000821D:OK
+```
+Indeed, after a read 24E1 is now confirmed to be zero!
+Next, again unlock, and erase 24E2
+
+```
+2024/10/29 09:24:01.901 <- i2c:3A:W3005554C      // unlock
+2024/10/29 09:24:01.903 -> i2c:3A:3005554C:OK
+2024/10/29 09:24:07.697 <- i2c:3A:W24E20000      // erase 24E2
+2024/10/29 09:24:07.700 -> i2c:3A:24E20000:OK
+2024/10/29 09:24:10.341 <- i2c:3A:W24E0R06       // read EEPROM
+2024/10/29 09:24:10.343 -> i2c:3A:24E0:R:070B00000000:OK
+```
+Now both 24E1 and 24E2 are erased, let's reprogram, using refresh rate 4.
+See datasheet:
+![datasheet_eemeas1_2_refresh_rate_table.png](media/datasheet_eemeas1_2_refresh_rate_table.png)
+Again we need to unlock the EEPROM, then write
+
+```
+2024/10/29 09:26:43.640 <- i2c:3A:W3005554C      // unlock EEPROM
+2024/10/29 09:26:43.643 -> i2c:3A:3005554C:OK
+2024/10/29 09:27:02.892 <- i2c:3A:W24E1840D      // write 24E1 = 840D
+2024/10/29 09:27:02.894 -> i2c:3A:24E1840D:OK
+2024/10/29 09:27:04.586 <- i2c:3A:W24E0R06       // check / read
+2024/10/29 09:27:04.588 -> i2c:3A:24E0:R:070B840D0000:OK
+2024/10/29 09:27:15.487 <- i2c:3A:W3005554C      // unlock EEPROM
+2024/10/29 09:27:15.490 -> i2c:3A:3005554C:OK
+2024/10/29 09:27:26.356 <- i2c:3A:W24E2841D      // write 24E2 = 841D
+2024/10/29 09:27:26.358 -> i2c:3A:24E2841D:OK
+2024/10/29 09:27:28.057 <- i2c:3A:W24E0R06       // check / read
+2024/10/29 09:27:28.060 -> i2c:3A:24E0:R:070B840D841D:OK
+```
+Now 24E1 and 24E2 are programmed to the desired value.
+Let's set the mode again to continuous, and check for a plausible temperature reading.
+```
+2024/10/29 09:27:41.615 <- i2c:3A:W3001R02
+2024/10/29 09:27:41.618 -> i2c:3A:3001:R:0000:OK    // REG_CONTROL is still at zero!
+2024/10/29 09:27:53.573 <- i2c:3A:W24E00006         // REG_CONTROL = 0006 or MODE = 3(CONTINUOUS)
+2024/10/29 09:27:53.575 -> i2c:3A:24E00006:OK
+2024/10/29 09:28:00.621 <- mv:3A                    // MV is the command 'Measure Value'
+2024/10/29 09:28:00.905 -> mv:3A:00808431:22.89,20.95
+```
+TA=22.89 Deg C
+TO=20.95 Deg C
+
+Oooh! One last thing, we talked about three words EE_MEAS0/1/2 but you might also want to check that EE_MEAS3(24E3) is FFFF.
+
+```
+2024/10/29 10:00:07.281 <- i2c:3A:W24E0R08
+2024/10/29 10:00:07.285 -> i2c:3A:24E0:R:070B840D841DFFFF:OK
+```