ESP8266 Community Forum

I'm trying to convert a couple of sketches surrounding the Adafruit library for Jpeg serial cameras to work on an ESP-01 with a 1m memory chip. While I may play later trying to direct stream the image to the Async server code (if I can figure that part out), for the time being I am trying to write a temporary file from the camera to SPIFFS, but as soon as I call the File.write(buffer, len) function, my Esp01 is crashing and resetting.

The Adafruit library uses a handle to SoftwareSerial which I have made sure is using ESPSoftwareSerial (using platformio to code in CLion). I'm not sure what the restrictions on the camera are, but the Adafruit code seems to suggest that you have to download the image data in blocks. Most of the examples I have seen either read 32 or 64 bytes at a time from the camera using the Adafruit library's read function.
(I have yet to find a spec on the camera's protocol, but the byte value is being sent with a 2 digit hex value in a hex character string. So unless it's an MSB/LSB value set, it would seem to have a 255 limit?)

The examples then usually write to an SD card using:
File imgFile = SD.open("IMAGE.JPG", FILE_WRITE);
For SPIFFS, I changed this to:
File imgFile = SPIFFS.open("/IMAGE.JPG", "w");

But as soon as I read the first 64 bytes and go to write them, the esp-01 crashes. Relevant code:




Code output with crash dump is below:

I just tried the same sketch on my WEMOS D1 Mini (ESP-12 based) using D3 and D4 (corresponding pins for GPIO0 and GPIO2) and got the same result.

I'm suspicious of the buffer datatype and/or pointer type.
uint8_t *buffer;

I tried using a fixed length buffer as I saw the adafruit code appears to use a fixed length buffer, but I must be doing something wrong. Obviously I couldn't assign the fixed length array based on how their examples worked, but their examples bothered me as it's passing a pointer back out to a private member. I wasn't sure how that would be handled in memory or how it would persist.
So I copied the library to my local directory and added a second signature to the function that would accept an array pointer in so I could use a fixed length array and it at least worked on the write without causing a crash. Problem is, I must be doing something wrong in my new function as I don't seem to be getting jpeg data in the file.
What's the recommended way to pass byte data back and forth from function calls? Passing a fixed-length array pointer in? They're using uint8_t*, shouldn't that be byte?

I see that the function readPicture() can return a 0 which indcates an error condition
Is it by any chance returning a 0 ?

Just to add:
AFAIK there is no difference between uint8_t and a byte