micropython SPI syntax problem for nodemcu

[yafimvar]

Hello, I am trying to communicate with DAC8004 using SPI and thonny micropython.
from the manufacturer manual the periphery is pins 12-15.

However when i try to run the following code of the manual, I get an error shown below that says thatI have a problem in the SPI command.
Where did i go wrong implementing this command?
Thanks.
`import machine
from machine import SPI, Pin
from machine import Pin
from time import sleep

cs=machine.Pin(15,machine.Pin.OUT)
spi=machine.SPI(0,baudrate=1000000,polarity=0,phase=0,bits=8,firstbit=machine.SPI.MSB,
sck=machine.Pin(14),
mosi=machine.Pin(13),
miso=machine.Pin(12))`

ERROR:
Traceback (most recent call last):
File "", line 10, in
ValueError:

https://docs.micropython.org/en/latest/esp8266/quickref.html#hardware-spi-bus
https://www.espressif.com/sites/default/files/documentation/0a-esp8266ex_datasheet_en.pdf

[davefes]

(SPI(0) is used for FlashROM and not available to users.)

try:
spi=machine.SPI(1,baudrate=1000000,polarity=0,phase=0,bits=8,firstbit=machine.SPI.MSB)

Also remove the commas at the line endings.

[yafimvar]

Hello, I need to send the following command for my DAC8004.
0000 0011 0000 1111 1111 1111 1111 0000
Its 32bit command.So i need to lower CS send 4 times 8 bits and raise CS.
from the manual below I see a sample of command spi.write(b"12345678").
The problem with this command is that its not binary.

In C i have written the following variables.
uint8_t B7_B0=0b11110000; //first 4 are dont care,first 4 bits data
uint8_t B15_B8=0b11111111;//data bits
uint8_t B23_B16=0b00000000;//channel A DATA total 0000 1111 1111 1111
uint8_t B31_B24=0b00000011;//write to buffer and update DAC ,Write /rest dont care
How do i send these variables in micropython?
Thanks.

https://docs.micropython.org/en/latest/library/machine.SPI.html

[davefes]

Maybe this helps:
https://stackoverflow.com/questions/62903377/python3-bytes-vs-bytearray-and-converting-to-and-from-strings

[yafimvar]

Hello , I have built the following code and defined hspi.
I defined buf2[0] but as you can see below i cant send it.
Where di i go wrong sending this variable?

---

import machine
from machine import Pin, SPI
from time import sleep
hspi = SPI(1, baudrate=1000000, polarity=0, phase=0)
#hspi = SPI(1) # sck=14 (scl), mosi=13 (sda), miso=12 (unused)
dc = Pin(4) # data/command
rst = Pin(5) # reset
cs = Pin(15) # chip select, some modules do not have a pin for this
cs.value(0)

cs.value(1)

---

hspi
HSPI(id=1, baudrate=1000000, polarity=0, phase=0)
buf2[0]
3
hspi.write(buf[0])
Traceback (most recent call last):
File "", line 1, in
TypeError: object with buffer protocol required

[yafimvar]

UPDATE:

Hello,my command is, SPI is defined as MSB first. did i send the data properly?
0000 0011 0000 1111 1111 1111 1111 0000
MSB *********************************** LSB

import machine
from machine import Pin, SPI
from time import sleep
hspi = SPI(1, baudrate=1000000, polarity=0, phase=0)
#hspi = SPI(1) # sck=14 (scl), mosi=13 (sda), miso=12 (unused)
buf = bytearray(4)
buf[0] = 0b11110000 # B7_B0
buf[1] = 0b11111111 # B15_B8
buf[2] = 0b00000000 # B23_B16
buf[3] = 0b00000011 # B31_B24

dc = Pin(4) # data/command
rst = Pin(5) # reset
cs = Pin(15) # chip select, some modules do not have a pin for this
cs.value(0)

Send the binary byte over SPI

hspi.write(buf[3:4]) # Send B31_B24
hspi.write(buf[2:3]) # Send B23_B16
hspi.write(buf[1:2]) # Send B15_B8
hspi.write(buf[0:1]) # Send B7_B0
cs.value(1)

[davefes]

A SPI expert is required. I think you can send all the bytes with one write. Also, I would look at doing a loopback test like:

 #  do a loop-back test first

    msg = 'Test'
    ser.write(msg)
    print ('message written')

    while True:
        new_msg = ser.read()
        if not new_msg:
            break

    print (f'{new_msg} \n')

connecting MISO and MOSI together.

Also, do you have to do some conversion and encoding (?) on your binary values?

[shariltumin]

As you have already found out, a value at an index is different from a slice of one byte when you are working with bytes or bytesarray.

>>> buf=b'\x03\x0f\xff\xf0'
>>> for i in range(4):
...     print(buf[i:i+1])
...
b'\x03'
b'\x0f'
b'\xff'
b'\xf0'

You can replace print() with hspi.write() in the for loop above.

If you need the reverse order, try this:

>>> for i in range(4,0,-1):
...     print(buf[i-1:i])
...
b'\xf0'
b'\xff'
b'\x0f'
b'\x03'

[shariltumin]

Sending the full 32bit command packet is probably the easiest and correct way to do this.

>>> cmd_hex=0x030ffff0      
>>> cmd=cmd_hex.to_bytes(4, 'big') # for big-endian byte order. 
>>> cmd
b'\x03\x0f\xff\xf0'
>>> cmd=cmd_hex.to_bytes(4, 'little') # for little-endian
>>> cmd
b'\xf0\xff\x0f\x03'