ULP I2C sensor readings.

[divekr]

Greetings!

Thanks for the great micropython, v1.18 is awesome for speed

I am trying to understand how to manage the obscure ULP code,
I found https://github.com/ThomasWaldmann/py-esp32-ulp, Thanks to Thomas, I've done a few things with that.
It has some limitations(exclude .macro etc), but almost part, It doesn't matter to work with,
and I found it "I2C_WR/RD" instructions available, so I am trying to communicate with I2C sensors.

From Espressif instruction set(https://docs.espressif.com/projects/esp ... n_set.html),
it says Slave address (in 7-bit format) has to be set in advance into SENS_I2C_SLAVE_ADDRx register field

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I2C_RD      0x10, 7, 0, 0      
// Read byte from sub-address 0x10 of slave with address set in SENS_I2C_SLAVE_ADDR0

I've tried to set SENS_I2C_SLAVE_ADDR0 within py-esp32-ulp,

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#define SENS_I2C_SLAVE_ADDR0  0x000007FF // Found in soc/sens_reg.h
#define RTC_I2C_SLAVE_ADDR_S  0 // Found in soc/rtc_i2c_reg.h
WRITE_RTC_REG(SENS_I2C_SLAVE_ADDR0,RTC_I2C_SLAVE_ADDR_S,8,0x68)

ValueError: invalid register base

I could not move forward from this,
so I've tried to follow the espressif's "Compiling the ULP Code" instruction,
I though it could be loaded into micropython.
But It generates a whole bunch of firmware file include ulp binary.

Could you help me to go further?
Using ThomasWaldmann/py-esp32-ulp will be the best way for me,
But the any way could be okay to get assembly bin files to load into micropython.

Thanks in advance,

Regards
Sam Lee

[Christian Walther]

I don’t think SENS_I2C_SLAVE_ADDR0 is the register’s address, that looks more like a mask.

Correlating esp32_technical_reference_manual_en.pdf section 30.8.1 to the stuff in the headers, try

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# from soc/soc.h
#define DR_REG_SENS_BASE                        0x3ff48800
# from soc/sens_reg.h
#define SENS_SAR_SLAVE_ADDR1_REG          (DR_REG_SENS_BASE + 0x003c)
#define SENS_I2C_SLAVE_ADDR0_S  11
WRITE_RTC_REG(SENS_SAR_SLAVE_ADDR1_REG, SENS_I2C_SLAVE_ADDR0_S, 11, 0x68)

I haven’t tested this and I have not used I2C on the ULP, only GPIOs.

[KJM]

I wish I could get my head around accessing the ULP from micropython! I found https://github.com/ThomasWaldmann/py-es ... counter.py but it crashes because there is no esp32_ulp on my machine. I found a lib of the same name @ https://github.com/ThomasWaldmann/py-es ... /esp32_ulp but it has no src_to_binary in it. I think ULP stands for 'unlikely little project'.

[divekr]

I don’t think SENS_I2C_SLAVE_ADDR0 is the register’s address, that looks more like a mask.

Correlating esp32_technical_reference_manual_en.pdf section 30.8.1 to the stuff in the headers, try

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# from soc/soc.h
#define DR_REG_SENS_BASE                        0x3ff48800
# from soc/sens_reg.h
#define SENS_SAR_SLAVE_ADDR1_REG          (DR_REG_SENS_BASE + 0x003c)
#define SENS_I2C_SLAVE_ADDR0_S  11
WRITE_RTC_REG(SENS_SAR_SLAVE_ADDR1_REG, SENS_I2C_SLAVE_ADDR0_S, 11, 0x68)

I haven’t tested this and I have not used I2C on the ULP, only GPIOs.

Dear Christian Walther,
I do really do thank you so much for your reply,
Your code is successfully converted to bin by py-esp32-ulp, so I could move forward.
I assuming that could register slave address, and I tried to initialize the I2C connection with below codes,

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// Select SDA/SCL pins to version 1, TOUCH2 and TOUCH3 (version 0 is TOUCH0 and TOUCH1)
WRITE_RTC_REG(RTC_IO_SAR_I2C_IO_REG, RTC_IO_SAR_I2C_SDA_SEL_S, RTC_IO_SAR_I2C_SDA_SEL_M, 1);
WRITE_RTC_REG(RTC_IO_SAR_I2C_IO_REG, RTC_IO_SAR_I2C_SCL_SEL_S, RTC_IO_SAR_I2C_SCL_SEL_M, 1);

I think RTC_IO_SAR_I2C_XXX_SEL_M values cause the error from header files, most of XXX_M has shift(<<) calcuration and some of them couldn't be converted. I manually put calcurated values, but there is "OverflowError: overflow converting long int to machine word"

I found

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WRITE_RTC_REG(SENS_SAR_SLAVE_ADDR1_REG, SENS_I2C_SLAVE_ADDR0_S, 11, 0x68)"
WRITE_RTC_REG(SENS_SAR_SLAVE_ADDR1_REG, SENS_I2C_SLAVE_ADDR0_S, SENS_I2C_SLAVE_ADDR0_M, 0x68);

SENS_I2C_SLAVE_ADDR0_M looks like 11, Can I ask you where can I find that value?

In espressif's header says it is,

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#define SENS_I2C_SLAVE_ADDR0_M  ((SENS_I2C_SLAVE_ADDR0_V)<<(SENS_I2C_SLAVE_ADDR0_S))
#define SENS_I2C_SLAVE_ADDR0_V  0x7FF
#define SENS_I2C_SLAVE_ADDR0_S  11

forgive my ignorances, I could not figure out 0x7FF << 11 = '0x3ff800' is "11"
This is becoming to decrypt a password for me


I just need to write and read a single 8bit to determine the sensor status like below,

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I2C_WR  0x40 ,0x0, 7, 0, 0
WAIT      2000
I2C_RD  0x00 ,7, 0, 0

I didn't think, that 3 lines to be this hard , I found micropython ULP references is more less than other parts.

Please help me to get there.......


regards,
Sam lee

[divekr]

I wish I could get my head around accessing the ULP from micropython! I found https://github.com/ThomasWaldmann/py-es ... counter.py but it crashes because there is no esp32_ulp on my machine. I found a lib of the same name @ https://github.com/ThomasWaldmann/py-es ... /esp32_ulp but it has no src_to_binary in it. I think ULP stands for 'unlikely little project'.

Dear KJM,
src_to_binary function is stated in __init__.py under esp32_ulp folder.
I found ThomasWaldmann/py-esp32-ulp is just library which converts some *.S(original ESP ULP code) into binary code.
src_to_binary makes it happen, once you convert binary code, You can run the ULP code without py-esp32-ulp library.
like,

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source = """
  move r2, 1
  sub r0, r2, r0 
  .....extra code.....
"""
binary = src_to_binary(source)
# you just print(binary) and copy into a variables, You can use it without the library anymore.

import esp32
binary = b"1\x00\x00\xd0\xe5\xaf,r,\x00@\x80+\x05\xcc........."
ulp = esp32.ULP()
load_addr, entry_addr = 0, 8
ulp.load_binary(load_addr, binary)
ulp.run(entry_addr)

PS: I am still looking for communicating with I2C sensor,
Please help me out

[Christian Walther]

I think RTC_IO_SAR_I2C_XXX_SEL_M values cause the error from header files, most of XXX_M has shift(<<) calcuration and some of them couldn't be converted. I manually put calcurated values, but there is "OverflowError: overflow converting long int to machine word"

I found

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WRITE_RTC_REG(SENS_SAR_SLAVE_ADDR1_REG, SENS_I2C_SLAVE_ADDR0_S, 11, 0x68)"
WRITE_RTC_REG(SENS_SAR_SLAVE_ADDR1_REG, SENS_I2C_SLAVE_ADDR0_S, SENS_I2C_SLAVE_ADDR0_M, 0x68);

SENS_I2C_SLAVE_ADDR0_M looks like 11, Can I ask you where can I find that value?

In espressif's header says it is,

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#define SENS_I2C_SLAVE_ADDR0_M  ((SENS_I2C_SLAVE_ADDR0_V)<<(SENS_I2C_SLAVE_ADDR0_S))
#define SENS_I2C_SLAVE_ADDR0_V  0x7FF
#define SENS_I2C_SLAVE_ADDR0_S  11

I don’t really understand the constants from the headers either, I assume they are mostly meant for use from C (which I haven’t done). I find it more helpful to look at the actual definitions of the registers in https://www.espressif.com/sites/default ... ual_en.pdf.

There (section 30.8.1, register 30.3) you can see that the ADDR0 field in the register at 0x003c from (RTC base address + 0x0800) starts at bit 11 and is 11 bits wide, which are the two numbers that you need to give to WRITE_RTC_REG(). One of them has a constant defined, SENS_I2C_SLAVE_ADDR0_S, so I used it, the other doesn’t, so I wrote a literal “11”.

I’m not sure what the purpose of SENS_I2C_SLAVE_ADDR0 is, seeing as it has the same value as SENS_I2C_SLAVE_ADDR0_V.
SENS_I2C_SLAVE_ADDR0_S seems to be the shift or start bit number.
SENS_I2C_SLAVE_ADDR0_V seems to be the mask you apply to the value before shifting it into place, which I see little use for.
SENS_I2C_SLAVE_ADDR0_M seems to be the mask indicating where in the register the field lives, which is useless in ULP assembly, because WRITE_RTC_REG() doesn’t take a mask, but start and width bit numbers.

In other words, you can use the …_S constant for the low_bit argument to WRITE_RTC_REG(), but there is no constant that I can see for the bit_width argument. It is not the …_M constant. (The value can be derived from it – but not in a way that is straightforward to write in source code).

I wish I could get my head around accessing the ULP from micropython! I found https://github.com/ThomasWaldmann/py-es ... counter.py but it crashes because there is no esp32_ulp on my machine. I found a lib of the same name @ https://github.com/ThomasWaldmann/py-es ... /esp32_ulp but it has no src_to_binary in it. I think ULP stands for 'unlikely little project'.

The way to install esp32_ulp is

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import upip; upip.install('micropython-py-esp32-ulp')

did you do that?

[divekr]

Dear Christian Walther,
It is so much grateful for me to have your reply again.
I think I am understanding "WRITE_RTC_REG", thanks to Christian.

As you said the ESP32 technical reference manual is so helpful for to understand ULP.
I am using ESP32-PICO-V3-02, so I've download "https://www.espressif.com/sites/default ... ual_en.pdf" it and looked up all the values.

I followed the chapter 30.6.1 Configuring RTC_I2C,I've come to this code,

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source = """
#define DR_REG_RTCIO_BASE            0x3ff48400
#define DR_REG_RTC_I2C_BASE          0x3ff48C00
#define DR_REG_SENS_BASE             0x3ff48800                  
#define SENS_SAR_SLAVE_ADDR1_REG     0x3FF4883C 
#define SENS_I2C_SLAVE_ADDR0         0x000007FF                  
#define SENS_I2C_SLAVE_ADDR0_S       11
#define SENS_I2C_SLAVE_ADDR1_S       0
#define RTC_IO_SAR_I2C_IO_REG        0x3FF484C4
#define RTC_IO_SAR_I2C_SDA_SEL_S     30
#define RTC_IO_SAR_I2C_SCL_SEL_S     28
#define RTC_I2C_SCL_LOW_PERIOD_REG   0x3FF48C00 
#define RTC_I2C_SCL_HIGH_PERIOD_REG  0x3FF48C38
#define RTC_I2C_SCL_LOW_PERIOD_S     0
#define RTC_I2C_SCL_HIGH_PERIOD_S    0
#define RTC_I2C_SDA_DUTY_REG         0x3FF48C30
#define RTC_I2C_SDA_DUTY_S           0
#define RTC_I2C_SCL_START_PERIOD_REG 0x3FF48C40
#define RTC_I2C_SCL_START_PERIOD_S   0
#define RTC_I2C_SCL_STOP_PERIOD_REG  0x3FF48C44
#define RTC_I2C_SCL_STOP_PERIOD_S    0
#define RTC_I2C_TIMEOUT_REG          0x3FF48C0C
#define RTC_I2C_TIMEOUT_S            0
#define RTC_I2C_CTRL_REG             0x3FF48C04
#define RTC_I2C_MS_MODE_S            4 
#define DR_REG_RTCIO_BASE            0x3ff48400
#define RTC_IO_TOUCH_PAD0_REG        0x3ff48494 
#define RTC_IO_TOUCH_PAD1_REG        0x3ff48498 
#define RTC_IO_TOUCH_PAD2_REG        0x3ff4849c 
#define RTC_IO_TOUCH_PAD3_REG        0x3ff484a0 
#define RTC_IO_TOUCH_PAD0_FUN_SEL_S  17 
#define RTC_IO_TOUCH_PAD1_FUN_SEL_S  17 

data:        .long 0
value:       .long 0

.global entry
entry:   
# Select SDA/SCL pins to version 1, TOUCH2 and TOUCH3 (version 0 is TOUCH0 and TOUCH1)
WRITE_RTC_REG(RTC_IO_SAR_I2C_IO_REG, RTC_IO_SAR_I2C_SDA_SEL_S, 2, 0)
WRITE_RTC_REG(RTC_IO_SAR_I2C_IO_REG, RTC_IO_SAR_I2C_SCL_SEL_S, 2, 0)
WRITE_RTC_REG(RTC_IO_TOUCH_PAD0_REG, RTC_IO_TOUCH_PAD0_FUN_SEL_S, 2, 3) 
WRITE_RTC_REG(RTC_IO_TOUCH_PAD1_REG, RTC_IO_TOUCH_PAD1_FUN_SEL_S, 2, 3) 

# WRITE_RTC_REG(rtc_reg, low_bit, bit_width, value)
WRITE_RTC_REG(SENS_SAR_SLAVE_ADDR1_REG, SENS_I2C_SLAVE_ADDR0_S, 11, 0x76)

# Set SCL speed to 100khz
WRITE_RTC_REG(RTC_I2C_SCL_LOW_PERIOD_REG, RTC_I2C_SCL_LOW_PERIOD_S, 19, 40)
WRITE_RTC_REG(RTC_I2C_SCL_HIGH_PERIOD_REG, RTC_I2C_SCL_HIGH_PERIOD_S, 20, 40)

# SDA duty (delay) cycles from falling edge of SCL when SDA changes.
WRITE_RTC_REG(RTC_I2C_SDA_DUTY_REG, RTC_I2C_SDA_DUTY_S, 20, 16)

# Number of cycles after start/stop condition
WRITE_RTC_REG(RTC_I2C_SCL_START_PERIOD_REG, RTC_I2C_SCL_START_PERIOD_S, 20, 30)
WRITE_RTC_REG(RTC_I2C_SCL_STOP_PERIOD_REG, RTC_I2C_SCL_STOP_PERIOD_S, 20, 44)

# cycles before timeout
WRITE_RTC_REG(RTC_I2C_TIMEOUT_REG, RTC_I2C_TIMEOUT_S, 20, 200)

# Set mode to master
WRITE_RTC_REG(RTC_I2C_CTRL_REG, RTC_I2C_MS_MODE_S, 1, 1)

JUMP running


reads:
ADD r0, r0, 1     # r0 += 1  
I2C_RD  0xa2, 7, 0, 0    # r0 = 0x171 //sensor returns 0x171
ADD r0, r0, 1	  # r0 += 1 
ST r0, r1, 4     # mem32[r1+4] = r0 // 0x172
JUMP exit

running:
MOVE r3, data   # r3 = 0  //(data)
LD r2, r3, 0      # [r3+0]) = r2
ADD r2, r2, 1    #  r2 += 1
ST r2, r3, 0     # [r3+0] = r2
JUMP reads

exit:
HALT
"""
from esp32_ulp import src_to_binary
from esp32 import ULP
from machine import mem32

binary = src_to_binary(source)
load_addr, entry_addr = 0, 8
ULP_MEM_BASE = 0x50000000
ULP_DATA_MASK = 0xFFFF  
ulp = ULP()
ulp.set_wakeup_period(0, 1000000)  
ulp.load_binary(load_addr, binary)
mem32[ULP_MEM_BASE + load_addr] = 0x1000
ulp.run(entry_addr)
while True:
	res1 = hex(mem32[ULP_MEM_BASE + load_addr] & ULP_DATA_MASK)
 	res2 = hex(mem32[ULP_MEM_BASE + load_addr+4] & ULP_DATA_MASK)
	print(res1,res2)

I am expecting,
0x1001 , 0x172
0x1002 , 0x172
0x1003 , 0x172
......

result is,
0x1001 , 0x0
0x1001 , 0x0
0x1001 , 0x0
......
Just for getting one bit data from I2C, generates that too long codes
it freezed after I2C_RD, it shows keep count up++ without I2C_RD line.
(it is hard to debug ULP, I've added a counter, but after read I2C value it is not counting up..)

I've read the references carefully, refered another c++ examples, tried different GPIO(TOUCH2,3)
,but It did not work. MCU doesn't lie to me, there is obviously something wrong,
but I don't know which I am missing ...

I think I might give up using ThomasWaldmann/py-esp32-ulp ...

[Christian Walther]

In can’t help you with I2C, but at a quick glance it looks like you’re not initializing r1.

[KJM]

Tnx for the src-to-binary shortcut suggestion I'll try that when I'm feeling braver. Sorry for intruding on your thread, I2C via ULP sounds like a great idea to me, hope you can get it working. I agree with Thomas https://github.com/ThomasWaldmann/py-es ... 1030615730 that we need a central resource where efforts ULP related might live, save people reinventing the wheel.

Christian, you mention you've done GPIO with ULP. I'd like to have a water meter pulse counter with the ULP. There are some implementations in C but I can't figure out how to use them from python. Do you know of a ULP counter program that counts pulses on a GPIO that I could substitute into https://github.com/ThomasWaldmann/py-es ... counter.py now that I have that working?