code stuck on `cam.capture`

using ov2640 camera with internal XCLK generation of 24MHz, and when i run
```python
import time

import board
import busio
import digitalio
from adafruit_ov2640 import OV2640, OV2640_COLOR_JPEG, OV2640_SIZE_QVGA

with busio.I2C(scl=board.GP5, sda=board.GP4, frequency=100_000) as bus:
print("[*] init camera")
cam = OV2640(
bus,
data_pins=[
board.GP6,
board.GP7,
board.GP8,
board.GP9,
board.GP10,
board.GP11,
board.GP12,
board.GP13,
],
clock=board.GP14,
href=board.GP15,
vsync=board.GP16,
mclk=None,
reset=board.GP2,
shutdown=board.GP17,
size=OV2640_SIZE_QVGA)

cam.colorspace = OV2640_COLOR_JPEG

print("[*] product id:", hex(cam.product_id))
print("[*] product version:", hex(cam.product_version))
print("[*] width:", cam.width, "height:", cam.height)

buf = bytearray(cam.capture_buffer_size)
print("[*] capturing")
cam.capture(buf)
print("[*] done")
```
the code is stuck on capture, any ideas ?

Begin by reproducing the provided OV2640 example with the listed pin assignments and internal 24MHz XCLK, then isolate where cam.capture blocks. Review the OV2640 capture entry point and document the confirmed cause and required configuration or fix once capture completes reliably.

Written by the indexing model from the issue text.