Hello,
I've been struggling with this for the last day or so and I can't seem
to figure out how to make it work.
I'll start out by saying that if there's a better approach, then I'm all ears.
I'm using the Adafruit Breakout board for the FTDI FT232H part. Along
with this comes the Python libraries and Adafruit libraries which I'm
using. I don't think that the libraries are the real issue here, but
I thought I should mention it just for the sake of information.
Basically I'm trying to write a block of unsigned bytes to the device
and read back an equal sized block of unsigned bytes. There's a
function that is provided called transfer(data_to_send, num_of_bytes)
that handles the heavy lifting. Unfortunately there seems to be a bug
in the part and if I attempt to send the entire block of bytes (64),
the device will lock up. I've been able to determine that if I send
16 bytes at a time, I'm okay.
So, I take my bytearray(64) and step through it 16 bytes at a time like this:
my function's main pieces are:
def transfer_byte_array():
MAX_LOOP_COUNT = 64
slice_size = 16
read_ary = bytearray(MAX_LOOP_COUNT)
scratch_ary = bytearray()
for step in range (0, MAX_LOOP_COUNT, slice_size):
scratch_ary = transfer(data_to_send, slice_size)
for bytes in range (0, slice_size):
read_ary = scratch_ary[bytes]
return(read_ary)
Ideally, I'd like to take the slice_size chunks that have been read
and concatenate them back togetjer into a long MAX_LOOP_COUNT size
array to pass back to the rest of my code. Eg:
read_ary = ary_slice[0] + ary_slice[1] + ary_slice[2] + ary_slice[3]
I know that the + version doesn't work (or didn't for me) but it is
just my attempt at illustrating the overall goal.
The problem that I repeatedly run into is with the line:
read_ary = scratch_ary[bytes] (or variants thereof)
The traceback is this:
Traceback (most recent call last):
File "SW8T_5.py", line 101, in <module>
loop_size = RSI_size_the_loop(Print)
File "/home/temp/Python_Scratch/examples/RSI.py", line 350, in
RSI_size_the_loop
read_ary.append(scratch_ary[singles])
TypeError: an integer or string of size 1 is required
or, one of the other common ones that I've seen is
TypeError: can't concat bytearray to list
This one is confusing because both of the operands are bytearry
types.. or at least I thought they should be...
when I try to replace the same line with :
read_ary += scratch_ary[bytes]
or
read_ary.append(scratch[bytes])
or
read_ary = read_ary + scratch_ary[bytes]
I'm obviously missing something fundamental here. Problem is I can't
seem to find any examples of people asking this question before on the
inter-webs..
Thank you in advance to taking time to read.
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